- Radical-Mediated 1,2-Formyl/Carbonyl Functionalization of Alkenes and Application to the Construction of Medium-Sized Rings
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A novel radical 1,2-formylfunctionalization of alkenes involving 1,2(4,5)-formyl migration triggered by addition of various carbon- and heteroatom-centered radicals to alkenes has been developed for the first time, thus providing straightforward access to diverse β-functionalized aldehydes with good efficiency, remarkable selectivity, and excellent functional group tolerance. Analogous transformations mediated by a keto-carbonyl migration have also been effected under similar conditions. This method was used to access ring systems including various benzannulated nine-, ten-, and eleven-membered rings, complex 6-5(6,7)-6(5) fused rings, and bridged rings with diverse functionalities.
- Li, Zhong-Liang,Li, Xiao-Hua,Wang, Na,Yang, Ning-Yuan,Liu, Xin-Yuan
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- The photoredox-catalyzed hydrosulfamoylation of styrenes and its application in the novel synthesis of naratriptan
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The hydrosulfamoylation of diverse aryl olefins provides facile access to alkylsulfonamides. Here we report a novel protocol utilizing radical-mediated addition and a thiol-assisted strategy to achieve the hydrosulfamoylation of diverse styrenes in modest to excellent yields under mild and economic reaction conditions. The methodology was found to provide an efficient and convenient approach for the synthesis of the anti-migraine drug naratriptan and it also can be used for the late-stage functionalization of natural products or medicines.
- Chen, Miaomiao,Ding, Xin,Gao, Yongyue,He, Xingxing,Kang, Jin,Lu, Aidang,Wang, Qingmin,Wang, Ziwen,Zhang, Mingjun
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supporting information
p. 9140 - 9143
(2021/09/14)
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- A Transient Directing Group Strategy Enables Enantioselective Multicomponent Organofluorine Synthesis
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The vicinal fluorofunctionalization of alkenes represents an expedient strategy for converting feedstock olefins into valuable fluorinated molecules and as such has garnered significant attention from the synthetic community; however, current methods remain limited in terms of scope and selectivity. Here we report the site-selective palladium-catalyzed three-component coupling of alkenylbenzaldehydes, arylboronic acids, and N-fluoro-2,4,6-trimethylpyridinium hexafluorophosphate facilitated by a transient directing group. The synthetically enabling methodology constructs vicinal stereocenters with excellent regio-, diastereo-, and enantioselectivities, forging products that map onto bioactive compounds.
- Engle, Keary M.,Gao, Yang,Li, Zi-Qi,Liu, Mingyu,Liu, Zhonglin,Oxtoby, Lucas J.,Tran, Van T.
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supporting information
p. 8962 - 8969
(2021/07/01)
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- Sequential Addition of Amines to Nitrile and Carbon-Carbon Multiple Bond: A Route to 7-Amino-5 H-dibenzo[ c,e]azepines
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A rare earth metal-catalyzed sequential inter- and intramolecular C-N bond formation of 2-nitrile-2′-alkenyl(alkynyl)biphenyls with amines has been developed, which provides a straightforward and efficient access to a range of new functional dibenzo[c,e]azepines. This represents the first examples of direct construction of seven-membered azaheterocycle from unsaturated nitriles and amines. Such transformations have the advantages of avoiding the use of additives, easily available starting materials, step- and high atom-economy, mild reaction conditions, and high selectivity.
- Hu, Kun,Liu, Ruiting,Zhou, Xigeng
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supporting information
p. 6946 - 6950
(2021/09/11)
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- Electrochemistry enabled selective vicinal fluorosulfenylation and fluorosulfoxidation of alkenes
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Both sulfur and fluorine play important roles in organic synthesis, the life science, and materials science. The direct incorporation of these elements into organic scaffolds with precise control of the oxidation states of sulfur moieties is of great significance. Herein, we report the highly selective electrochemical vicinal fluorosulfenylation and fluorosulfoxidation reactions of alkenes, which were enabled by the unique ability of electrochemistry to dial in the potentials on demand. Preliminary mechanistic investigations revealed that the fluorosulfenylation reaction proceeded through a radical-polar crossover mechanism involving a key episulfonium ion intermediate. Subsequent electrochemical oxidation of fluorosulfides to fluorosulfoxides were readily achieved under a higher applied potential with the adventitious H2O in the reaction mixture.
- Jiang, Yimin,Shi, Zhaojiang,Wu, Jinnan,Wu, Shaofen,Ye, Keyin,Yu, Yi,Yuan, Yaofeng
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supporting information
(2021/11/17)
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- Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
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We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
- Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
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supporting information
p. 9680 - 9683
(2021/09/30)
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- Synthesis method of monosubstituted styrene
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The invention discloses a synthetic method of monosubstituted styrene. According to the method, monosubstituted benzaldehyde and methyltriphenylphosphonium bromide are used as initial raw materials, tetrahydrofuran is used as a solvent, strong base without nitrogen protection and low-temperature reaction conditions is used for reaction at normal temperature and normal pressure, and after the reaction is finished, a flash column chromatography method is used for post-treatment to obtain monosubstituted styrene. According to the method, water-free and oxygen-free harsh operation conditions are avoided, and the synthesis cost is reduced; the post-treatment process is simplified, quenching and extraction operations are not needed, the post-treatment time is shortened, a large amount of eluentdoes not need to be used, and the product loss is reduced.
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Paragraph 0038-0042; 0055-0064; 0065-0068
(2020/05/05)
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- Iron-Catalyzed Direct Julia-Type Olefination of Alcohols
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Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- A nd N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.
- Landge, Vinod G.,Babu, Reshma,Yadav, Vinita,Subaramanian, Murugan,Gupta, Virendrakumar,Balaraman, Ekambaram
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p. 9876 - 9886
(2020/09/03)
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- Catalytic Systems for Production of 1-Hexene by Selective Ethylene Trimerization
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Abstract: New chromium complexes with diphosphine ligands have been obtained by the reaction of chromium(III) hexahydrate and diphosphines in acetone. The structure of chromium(III) complex 4 containing water molecule and 1,2-bis(diphenylphosphino)benzene as ligands and that of two chromium(III) complexes (12 and 13) with 1,2-bis(diphenylphosphino)benzene ligands containing alkenyl substituents in the ortho-position of one of the phenyl groups at the phosphorous atom have been determined using X-ray diffraction analysis. The catalytic properties of the obtained complexes in the composition of catalytic systems for ethylene trimerization have been studied. It has been shown that the obtained series of catalytic systems manifests high activity in the process of ethylene trimerization to 1-hexene, with the process selectivity exceeding 94%. The highest value of productivity amongst known selective catalytic systems for trimerization was achieved using a chromium complex 13 bearing the 2-methylprop-1-enyl group at the ortho-position of one of the phenyl groups. The influence of temperature, pressure, the nature of the solvent and the composition of the catalytic system on the parameters of the process of ethylene trimerization to form 1-hexene has been determined.
- Afanas’ev, V. V.,Bespalova, N. B.,Cheredilin, D. N.,Kozlova, G. A.,Senin, A. A.,Sheloumov, A. M.
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- AuCl3-Catalyzed Ring-Closing Carbonyl–Olefin Metathesis
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Compared with the ripeness of olefin metathesis, exploration of the construction of carbon–carbon double bonds through the catalytic carbonyl–olefin metathesis reaction remains stagnant and has received scant attention. Herein, a highly efficient AuCl3-catalyzed intramolecular ring-closing carbonyl–olefin metathesis reaction is described. This method features easily accessible starting materials, simple operation, good functional-group tolerance and short reaction times, and provides the target cyclopentenes, polycycles, benzocarbocycles, and N-heterocycle derivatives in good to excellent yields.
- Wang, Rui,Chen, Yi,Shu, Mao,Zhao, Wenwen,Tao, Maoling,Du, Chao,Fu, Xiaoya,Li, Ao,Lin, Zhihua
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supporting information
p. 1941 - 1946
(2020/02/11)
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- Carbonylative cycloaddition between two different alkenes enabled by reactive directing groups: Expedited construction of bridged polycyclic skeletons
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A novel palladium-catalyzed highly selective hydrocarbonylative cycloaddition reaction with two different alkenes in the presence of CO enabled by a reactive directing-group is developed, which offers efficient and convenient access to lactone-containing bridged polycyclic compounds in high yield with high chemo- and stereoselectivities.
- Gao, Bingjian,Zou, Suchen,Yang, Guoqing,Ding, Yongzheng,Huang, Hanmin
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supporting information
p. 12198 - 12201
(2020/10/26)
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- Two-Step Procedure for the Synthesis of 1,2,3,4-Tetrahydro-quinolines
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A new two-step procedure that includes an initial regioselective intermolecular hydroaminoalkylation of ortho-chlorostyrenes with N-methylanilines and a subsequent intramolecular Buchwald–Hartwig amination gives direct access to 1,2,3,4-tetrahydroquinolines. The hydroaminoalkylation reaction of the ortho-chlorostyrenes is catalyzed by a 2,6-bis(phenylamino)pyridinato titanium complex which delivers the linear regioisomers with high selectivities. In addition, the formation of unexpected dihydroaminoalkylation products from styrenes and N-methylanilines is reported.
- Doye, Sven,Warsitz, Michael
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p. 6997 - 7014
(2020/12/01)
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- Carbosulfenylation of Alkenes with Organozinc Reagents and Dimethyl(methylthio)sulfonium Trifluoromethanesulfonate
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The electrophilic alkylthiolation of alkenes, initiated by dimethyl(methylthio)sulfonium salts and the subsequent addition of various heteronucleophilies has been well-established. Regarding the use of carbon nucleophiles, however, only carefully designed sp-type carbon sources have been successfully applied. We herein present our findings on the methylthiolation of alkenes with dimethyl(methylthio)sulfonium trifluoromethanesulfonate, followed by carbon-carbon bond formation in the presence of organozinc reagents, thus achieving a catalyst-free protocol toward to the carbosulfenylation of alkenes.
- Tang, Meizhong,Han, Shuxiong,Huang, Shenglan,Huang, Shenlin,Xie, Lan-Gui
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supporting information
p. 9729 - 9734
(2020/12/21)
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- Tandem Reaction Approaches to Isoquinolones from 2-Vinylbenzaldehydes and Anilines via Imine Formation-6π-Electrocyclization-Aerobic Oxidation Sequence
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Two distinctive transition-metal-promoted aerobic oxidation protocols have been developed for the synthesis of isoquinolones from 2-vinylbenzaldehydes and aniline derivatives. Thus, the one-pot tandem reaction sequence of imine formation, thermal 6π-electrocyclization, followed by either Cu(OAc)2-mediated or Pd(OAc)2-catalyzed aerobic oxidation protocol allowed the ready access to isoquinolone derivatives. The control experiments revealed that the 1,2-dihydroisoquinoline intermediates from the 6π-electrocyclization of 1-azatrienes were aerobically oxidized to isoquinolones in the presence of either Cu(OAc)2 or Pd(OAc)2 catalyst.
- Lee, Jiyeon,Kim, Hun Young,Oh, Kyungsoo
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supporting information
p. 474 - 478
(2020/01/21)
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- Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
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Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramolecular carboamination.
- Chang, Xin,Chen, Hong-Chao,Li, Chuan-Ying,Ma, Pei-Long,Wang, Peng
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supporting information
p. 8937 - 8940
(2020/04/30)
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- Preparation method of silicon spiro compound (by machine translation)
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The invention discloses a preparation method of a silicon spiro compound. The invention provides a preparation method of a silicon spiro compound as shown in a formula II, which comprises the following steps: in a solvent, a compound represented by the formula III is subjected to cyclization reaction under the presence of a monovalent rhodium catalyst and a phosphine ligand to obtain the silicon spiro compound as shown in the formula II. The preparation method of the silicon spiro compound can be simple. , The establishment of the silicon spiro compound is realized conveniently and efficiently. (by machine translation)
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Paragraph 0240-0242
(2020/06/17)
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- 6,7-Benzotropolone Syntheses Based on Ring-Closing Metatheses and Four-Electron Oxidations
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Four homoallyl ortho-vinylaryl ketones (10a-d) – 1,8-dienes of sorts – were prepared by several approaches. In the presence of 1–2 mol-% Grubbs-II catalyst, they ring-closed to give 6,7-dihydrobenzocyclohepten-5-ones (11a-d) in 90–96 % yield. With SeO2 the parent compound (11a) delivered benzocyclohepten-5-one (13a) and/or selenium-containing compounds (18–22) but no more than traces of 6,7-benzotropolone (5a). However, 5a was accessible from compound 11a via the sodium enolate and allowing it to react with a stream of oxygen (43 % yield). The sodium enolates of the substituted 6,7-dihydrobenzocyclohepten-5-ones 11b–d and oxygen underwent analogous 4-electron oxidations. This furnished the substituted 6,7-benzotropolones 11b-d. In contrast, the corresponding lithium enolates were inert towards oxygen. The 6,7-dihydrobenzocyclohepten-5-one 11d was also accessed differently, namely by a Grubbs-II catalyst-mediated RCM/C=C migration tandem reaction of the allyl ortho-allylaryl ketone 73 – another 1,8-diene of sorts (90 % yield).
- Brückner, Reinhard,Fernandes, Manuel A.,Gemander, Manuel,Green, Ivan R.,Kreibich, Michael,Peter, David,Yadav, Dharmendra B.,de Koning, Charles B.,van Otterlo, Willem A. L.
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- Enantioselective Construction of Spiro Quaternary Carbon Stereocenters via Pd-Catalyzed Intramolecular α-Arylation
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We herein report the development of a sterically hindered and electron-rich P-chiral monophosphorus biaryl ligand that has enabled a general and efficient enantioselective intramolecular α-arylation, providing access to a wide series of [4.4], [4.5], and [4.6]-spirocycles with chiral benzylic quaternary carbons in high yields with good to excellent enantioselectivities. A pronounced water effect on enantioselectivity is observed.
- Wu, Ting,Kang, Xuehua,Bai, Heng,Xiong, Wenrui,Xu, Guangqing,Tang, Wenjun,Tang, Wenjun
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supporting information
p. 4602 - 4607
(2020/06/29)
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- Synthesis of Unprotected 2-Arylglycines by Transamination of Arylglyoxylic Acids with 2-(2-Chlorophenyl)glycine
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The transamination of α-keto acids with 2-phenylglycine is an effective methodology for directly synthesizing unprotected α-amino acids. However, the synthesis of 2-arylglycines by transamination is problematic because the corresponding products, 2-arylglycines, transaminate the starting arylglyoxylic acids. Herein, we demonstrate the use of commercially available l-2-(2-chlorophenyl)glycine as the nitrogen source in the transamination of arylglyoxylic acids, producing the corresponding 2-arylglycines without interference from the undesired self-transamination process.
- Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
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p. 11047 - 11059
(2020/10/12)
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- The Different Faces of [Ru(bpy)3Cl2] and fac[Ir(ppy)3] Photocatalysts: Redox Potential Controlled Synthesis of Sulfonylated Fluorenes and Pyrroloindoles from Unactivated Olefins and Sulfonyl Chlorides
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A cascade alkene sulfonylation that simultaneously forges C-S and C-C bonds is a highly efficient and powerful approach for directly accessing structurally diverse sulfonylated compounds in a single operation. The reaction was enabled by visible-light-mediated regioselective radical addition of sulfonyl chlorides to 2-arylstyrenes using fac[Ir(ppy)3] as a photocatalyst, demonstrating its unique role in a photocascade process to execute atom transfer radical addition (ATRA) followed by photocyclization. A new class of sulfonyl-substituted fluorenes and pyrroloindoles, which are useful in the field of photoelectronic materials and medicinal chemistry, was produced in excellent yields by this photocascade reaction. In contrast, the cyclization was interrupted when using the [Ru(bpy)3Cl2] catalyst having lower reduction potential, leading only to the formation of a C-S bond and the production of acyclic sulfonylated 2-arylstyrenes under identical reaction conditions. The synthetic utility of the present room-temperature photocatalysis is enhanced by the broad availability of bench-stable sulfonyl chlorides and unactivated olefins, thereby providing a cost-effective and broad-scope protocol.
- Pagire, Santosh K.,Kumagai, Naoya,Shibasaki, Masakatsu
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supporting information
p. 7853 - 7858
(2020/10/12)
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- MODULATORS OF HEMOGLOBIN
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The present disclosure relates generally to compounds and pharmaceutical compositions suitable as modulators of hemoglobin, and methods for their use in treating disorders mediated by hemoglobin.
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Paragraph 0450-0451
(2020/06/08)
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- A Sequential Pd-AAA/Cross-Metathesis/Cope Rearrangement Strategy for the Stereoselective Synthesis of Chiral Butenolides
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A practical and highly enantio- (up to 94:6 er) and diastereoselective (up to >20:1 dr) synthesis of I-butenolides bearing two adjacent stereogenic centers is reported featuring a sequential direct palladium-catalyzed asymmetric allylic alkylation/(E)-selective cross-metathesis/[3,3]-sigmatropic Cope rearrangement from readily available α-substituted (5H)-furan-2-ones.
- Aubert, Sidonie,Katsina, Tania,Arseniyadis, Stellios
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supporting information
p. 2231 - 2235
(2019/03/29)
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- A [...] reagent catalytic synthesis method and its application (by machine translation)
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The invention provides a method for catalytic synthesis of [...] reagent method and its application, the [...] reagent of formula (1) as shown in the structure of the organic solution: Its catalytic synthesis method is: under protection of inert gas, (II) shown [...] catalyst copper complex and active zinc powder added to the organic solvent, under a certain temperature [...] methyl bromide, then temperature reaction until the zinc powder the reaction is complete, the obtained white suspension is [...] reagent. (II), the invention compared with the prior art, the major advantage of: provides a [...] reagent catalytic synthesis method, is formed from a copper compound as a catalyst in the synthesis of the reagent [...] effect, and in the carbonyl of methylene compounds have been obtained in the application. (by machine translation)
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Paragraph 0039; 0040; 0043; 0044; 0046
(2018/04/28)
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- Copper-Catalyzed Oxidative Difunctionalization of Terminal Unactivated Alkenes
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The copper(II)-promoted free-radical oxidative difunctionalization of terminal alkenes to access ketoazides by utilizing molecular oxygen has been reported. A series of styrene derivatives have been evaluated and were found to be compatible to give the desired difunctionalized products in moderate to good yields. The role of molecular oxygen both as an oxidant and oxygen atom source in this catalytic transformation has been unquestionably demonstrated by 18O-labeling studies and a radical mechanistic pathway involving the oxidative formation of azidyl radicals is also designed. This environment-friendly catalytic oxidative protocol can transform aldehyde to nitrile.
- Hussain, Muhammad Ijaz,Feng, Yangyang,Hu, Liangzhen,Deng, Qingfu,Zhang, Xiaohui,Xiong, Yan
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p. 7852 - 7859
(2018/05/30)
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- Synthesis of functionalized helical BN-benzo[c] phenanthrenes
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A novel parent BN-benzo[c]phenanthrene, with helical chirality and remarkable structural features, has been easily obtained in three steps with a global yield of 55%. Moreover, Cl-substituted derivatives have been prepared and these have served as useful starting materials for the development of palladium-catalyzed cross-coupling reactions.
- Abengózar, Alberto,García-García, Patricia,Sucunza, David,Pérez-Redondo, Adrián,Vaquero, Juan J.
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supporting information
p. 2467 - 2470
(2018/03/21)
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- Synthesis of Phthalans Via Copper-Catalyzed Enantioselective Cyclization/Carboetherification of 2-Vinylbenzyl Alcohols
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Enantiomerically enriched phthalans were synthesized efficiently via an enantioselective copper-catalyzed alkene carboetherification reaction. In this reaction, 2-vinylbenzyl alcohols enantioselectively cyclize then couple with vinylarenes. The utility of the method was demonstrated by the enantioselective synthesis of (R)-fluspidine, a σ1 receptor ligand.
- Chen, Dake,Chemler, Sherry R.
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supporting information
p. 6453 - 6456
(2018/10/24)
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- Intramolecular Acetyl Transfer to Olefins by Catalytic C?C Bond Activation of Unstrained Ketones
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A rhodium-catalyzed intramolecular acetyl-group transfer has been achieved through a “cut and sew” process. The challenge arises from the existence of different competitive pathways. Preliminary success has been achieved with unstrained enones that contain a biaryl linker. The use of an electron-rich N-heterocycilc carbene (NHC) ligand is effective to inhibit undesired β-hydrogen elimination. Various 9,10-dihydrophenanthrene derivatives can be prepared with excellent functional-group compatibility. The 13C-labelling study suggests that the reaction begins with cleavage of the unstrained C?C bond, followed by migratory insertion and reductive elimination.
- Rong, Zi-Qiang,Lim, Hee Nam,Dong, Guangbin
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supporting information
p. 475 - 479
(2018/02/21)
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- Method for synthesizing olefin compound by photo-induced one-pot process
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The invention discloses a method for synthesizing an olefin compound by a photo-induced one-pot process. The method comprises the following step of subjecting a halohydrocarbon and an aldehyde compound to a reaction under the condition of irradiation in an inert atmosphere by taking alkali metal carbonate as a base, taking an organic phosphine compound as an adjuvant and taking a photosensitizer as a catalyst, thereby obtaining the olefin compound. According to the method disclosed by the invention, the olefin compound is produced from the halohydrocarbon and the aldehyde compound in a high-yield manner under the condition of irradiation in the inert atmosphere under normal-temperature reaction conditions by taking acetonitrile, DMF (N,N-dimethylformamide) or DMA (N,N-dimethylacetamide) asa solvent, taking an organic phosphine reagent as a reaction adjuvant, taking the alkali metal carbonate as the base and taking the photosensitizer as the catalyst. Compared with the conventional olefin synthesis methods, the method disclosed by the invention has the obvious advantages that the reaction raw materials are readily available, the tolerance to a variety of functional groups on halohydrocarbons and aldehydes is high, the yield is high, the separation and purification of a product are simple and convenient, and the like.
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Paragraph 0065-0067
(2018/11/03)
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- Electronically Mismatched Cycloaddition Reactions via First-Row Transition Metal, Iron(III)-Polypyridyl Complex
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The iron(III)-polypyridyl complex and its derivatives showed sufficient oxidizing potential to act as a one-electron oxidant, producing radical cations from olefins and promoting the efficient radical cation [2 + 2] and [2 + 4] cycloaddition reactions. Subsequent chain propagation afforded trisubstituted cyclobutane or cyclohexene derivatives, and this facile route enables the replacement of rare metals with sustainable, green, and inexpensive iron in radical cation cycloadditions.
- Shin, Jung Ha,Seong, Eun Young,Mun, Hyeon Jin,Jang, Yu Jeong,Kang, Eun Joo
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supporting information
p. 5872 - 5876
(2018/09/25)
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- Chemoselectivity in the Kosugi-Migita-Stille coupling of bromophenyl triflates and bromo-nitrophenyl triflates with (ethenyl)tributyltin
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Kosugi-Migita-Stille cross coupling reactions of (ethenyl)tributyltin with all isomeric permutations of bromophenyl triflate and bromo-nitrophenyl triflate were examined in order to determine the chemoselectivity of carbon-bromine versus carbon-triflate bond coupling under different reaction conditions. In general, highly selective carbon-bromine bond cross couplings were observed using for example bis(triphenylphosphine)palladium dichloride (2 mol-%) in 1,4-dioxane at reflux. In contrast, reactions using the same pre-catalyst but in the presence of a three-fold excess of lithium chloride in N,N-dimethylformamide at ambient temperature were in most cases selective for coupling at the carbon-triflate bond. Overall, isolated yields and the selectivity for carbon-bromine bond coupling were significantly higher compared to carbon-triflate bond coupling.
- Ansari, Nurul N.,Cummings, Matthew M.,S?derberg, Bj?rn C.G.
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p. 2547 - 2560
(2018/04/20)
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- A palladium-catalyzed intramolecular Heck/Hydrogenation approach towards the synthesis of praziquantel
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Starting from 3-methoxy N-acylpyrazinium salts, a new approach towards the synthesis of the antischistosomal drug praziquantel (PZQ) has been developed. Utilization of a palladium-catalyzed intramolecular Heck reaction to form dehydro-PZQ followed by a Hydrogenation step, in a stepwise or one-pot manner, allowed for the gram scale synthesis of PZQ in 4 or 5 steps and in good overall yields. This methodology proved to be well suited for generating the pyrazino[1,2-a] isoindole and pyrazino[1,2-a] benzazepine analogues of PZQ.
- Williams, Alfred L.,St. Hilaire, Valentine R.
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p. 6712 - 6717
(2017/10/25)
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- Highly Selective Semihydrogenation of Alkynes to Alkenes by Using an Unsupported Nanoporous Palladium Catalyst: No Leaching of Palladium into the Reaction Mixture
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We report the highly chemoselective and stereoselective semihydrogenation of alkynes to Z-internal and terminal alkenes by using unsupported nanoporous palladium (PdNPore) as a heterogeneous catalyst under mild reaction conditions (room temperature and 1 atm of H2). The semihydrogenation of various terminal/internal and aromatic/aliphatic alkynes afforded the corresponding alkenes in good chemical yields with high selectivities. PdNPore further showed high chemoselectivity toward terminal alkynes in the presence of internal alkynes, which has not yet been achieved using supported palladium nanoparticle catalysts. H-H heterolysis of H2 on the surface of PdNPore was strongly suggested by deuterium labeling experiments. No Pd leached from PdNPore during the reaction, and the catalyst was easily recovered and reused without a loss of activity.
- Lu, Ye,Feng, Xiujuan,Takale, Balaram S.,Yamamoto, Yoshinori,Zhang, Wei,Bao, Ming
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p. 8296 - 8303
(2017/12/08)
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- Intramolecular Crossed [2+2] Photocycloaddition through Visible Light-Induced Energy Transfer
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Herein, we present the intramolecular [2+2] cycloadditions of dienones promoted through sensitization, using a polypyridyl iridium(III) catalyst, to form bridged cyclobutanes. In contrast to previous examples of straight [2+2] cycloadditions, these efficient crossed additions were achieved under irradiation with visible light. The reactions delivered desired bridged benzobicycloheptanone products with excellent regioselectivity in high yields (up to 96%). This process is superior to previous syntheses of benzobicyclo[3.1.1]heptanones, which are readily converted to B-norbenzomorphan analogues of biological significance. Electrochemical, computational, and spectroscopic studies substantiated the mechanism of triplet energy transfer and explained the unusual regiocontrol.
- Zhao, Jiannan,Brosmer, Jonathan L.,Tang, Qingxuan,Yang, Zhongyue,Houk,Diaconescu, Paula L.,Kwon, Ohyun
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supporting information
p. 9807 - 9810
(2017/08/03)
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- α-Alkylidene-γ-butyrolactone Formation via Bi(OTf)3-Catalyzed, Dehydrative, Ring-Opening Cyclizations of Cyclopropyl Carbinols: Understanding Substituent Effects and Predicting E/Z Selectivity
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A Bi(OTf)3-catalyzed ring-opening cyclization of (hetero)aryl cyclopropyl carbinols to form α-alkylidene-γ-butyrolactones (ABLs) is reported. This transformation represents different chemoselectivity from previous reports that demonstrated formation of (hetero)aryl-fused cyclohexa-1,3-dienes upon acid-promoted cyclopropyl carbinol ring opening. ABLs are obtained in up to 89% yield with a general preference for the E-isomers. Mechanistically, Bi(OTf)3 serves as a stable and easy to handle precursor to TfOH. TfOH then catalyzes the formation of cyclopropyl carbinyl cations, which undergo ring opening, intramolecular trapping by the neighboring ester group, subsequent hydrolysis, and loss of methanol resulting in the formation of the ABLs. The nature and relative positioning of the substituents on both the carbinol and the cyclopropane determine both chemo- and stereoselective outcomes. Carbinol substituents determine the extent of cyclopropyl carbinyl cation formation. The cyclopropane donor substituents determine the overall reaction chemoselectivity. Weakly stabilizing or electron-poor donor groups provide better yields of the ABL products. In contrast, copious amounts of competing products are observed with highly stabilizing cyclopropane donor substituents. Finally, a predictive model for E/Z selectivity was developed using DFT calculations.
- Sandridge, Matthew J.,McLarney, Brett D.,Williams, Corey W.,France, Stefan
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p. 10883 - 10897
(2017/10/27)
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- Palladium-Catalyzed Ring-Forming Aminoalkenylation of Alkenes with Aldehydes Initiated by Intramolecular Aminopalladation
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A palladium-catalyzed aminopalladation reaction followed by nucleophilic addition with aldehydes and dehydration is described. This direct and operationally simple procedure provides a rapid and reliable approach to a wide range of functionalized tetrahydroisoquinolines with high selectivity. Mechanistic studies disclosed that the nucleophilic addition, performed via a highly ordered transition-state, is the turnover-limiting step in which the inherent β-hydride elimination of the key Csp3?Pd species was controlled by the confined conformation and the nucleophilicity of the Csp3?Pd bond was enhanced by the strong electron-donating effect of the nitrogen atom.
- Hu, Yue,Xie, Yinjun,Shen, Zhiqiang,Huang, Hanmin
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supporting information
p. 2473 - 2477
(2017/02/23)
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- C- ARYL GLYCOSID DERIVATIVES, PHARMACEUTICAL COMPOSITION, PREPARATION PROCESS AND USES THEREOF
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This invention relates to a kind of C-aryl glycoside derivatives, its pharmaceutical compositions, preparation methods, and uses thereof. The preparation method comprises: method 1: in a solvent, deprotecting the acetyl protecting groups of compound 1-f in the presence of a base; method 2: 1) compound 2-g reacts with via Mitsunobu reaction; 2) deprotecting the acetyl protecting groups of compound 2-f obtained from step 1; method 3: 1) compound 2-g reacts with via nucleophilic substitution reaction; 2) deprotecting the acetyl protecting groups of compound 3-f obtained from step 1. The pharmaceutical composition comprises a kind of C-aryl glycoside derivatives; it's pharmaceutically acceptable salts and/or prodrugs thereof and excipient thereof. This invention further relates to a kind of C-aryl glycoside derivatives, it's pharmaceutically acceptable salts or pharmaceutical compositions thereof for the use in preparation of a SGLT inhibitor. The C-aryl glycoside derivatives of this invention provides a new direction for the study of SGLT inhibitors.
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Paragraph 0142; 0143
(2017/04/19)
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- Modular Construction of Fluoroarenes from a New Difluorinated Building Block by Cross-Coupling/Electrocyclisation/Dehydrofluorination Reactions
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Palladium-catalysed coupling reactions based on a novel and easy-to-synthesise difluorinated organotrifluoroborate were used to assemble precursors to 6π-electrocyclisations of three different types. Electrocyclisations took place at temperatures between 90 and 240 °C, depending on the central component of the π-system; nonaromatic trienes were most reactive, but even systems that required the temporary dearomatisation of two arenyl subunits underwent electrocyclisation, albeit at elevated temperatures. Photochemical conditions were effective for these more demanding reactions. The package of methods delivered a structurally diverse set of fluorinated arenes, spanning a 20 kcal mol?1range of reactivity, by a flexible route.
- Percy, Jonathan M.,Emerson, Helena,Fyfe, James W. B.,Kennedy, Alan R.,Maciuk, Sergej,Orr, David,Rathouská, Lucie,Redmond, Joanna M.,Wilson, Peter G.
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supporting information
p. 12166 - 12175
(2016/08/16)
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- Synthesis of 1,3-Substituted Cyclobutanes by Allenoate-Alkene [2 + 2] Cycloaddition
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A method for the [2 + 2] cycloaddition of terminal alkenes with allenoates is presented. This process allows for the rapid synthesis of 1,3-substituted cyclobutanes in high yield under simple and robust reaction conditions.
- Conner, Michael L.,Brown, M. Kevin
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p. 8050 - 8060
(2016/09/09)
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- Structurally Defined Molecular Hypervalent Iodine Catalysts for Intermolecular Enantioselective Reactions
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Molecular structures of the most prominent chiral non-racemic hypervalent iodine(III) reagents to date have been elucidated for the first time. The formation of a chirally induced supramolecular scaffold based on a selective hydrogen-bonding arrangement provides an explanation for the consistently high asymmetric induction with these reagents. As an exploratory example, their scope as chiral catalysts was extended to the enantioselective dioxygenation of alkenes. A series of terminal styrenes are converted into the corresponding vicinal diacetoxylation products under mild conditions and provide the proof of principle for a truly intermolecular asymmetric alkene oxidation under iodine(I/III) catalysis.
- Haubenreisser, Stefan,W?ste, Thorsten H.,Martnez, Claudio,Ishihara, Kazuaki,Muiz, Kilian
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supporting information
p. 413 - 417
(2016/01/25)
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- An Efficient Synthesis of Benzazocines by Gold(I)-Catalyzed Tandem 1,2-Acyloxy Shift/[3+2] Cycloaddition of Terminal 1,9-Enynyl Esters
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An effective synthesis of structurally diverse benzazocines was accomplished in good to excellent chemical yields (55–82 %) through a gold(I)-catalyzed cascade reaction involving tandem 1,2-acyloxy shift/[3+2] cycloaddition of terminal 1,9-enynyl esters. The reaction proceeds under extremely mild conditions and represents one of the relatively few transition-metal-catalyzed intramolecular cycloaddition reactions for the synthesis of benzazocines.
- Feng, Shangbiao,Wang, Zhengshen,Zhang, Weiwei,Xie, Xingang,She, Xuegong
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supporting information
p. 2167 - 2172
(2016/08/12)
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- Cycloaddition Reaction of Vinylphenylfurans and Dimethyl Acetylenedicarboxylate to [8 + 2] Isomers via Tandem [4 + 2]/Diradical Alkene-Alkene Coupling/[1,3]-H Shift Reactions: Experimental Exploration and DFT Understanding of Reaction Mechanisms
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An experimental test of designed [8 + 2] reaction of vinylphenylfuran and dimethyl acetylenedicarboxylate (DMAD) has been carried out, showing that the reaction gave unexpected addition products under different conditions. When the reaction was conducted under thermal conditions in toluene, expoxyphenanthrene, which was named as a [8 + 2] isomer, was generated. The scope of this reaction has been investigated in the present study. In addition, experiments and DFT calculations have been conducted to investigate how the reaction between vinylphenylfuran and DMAD took place. Surprisingly, the reaction did not involve the expected [8 + 2] intermediate, o-quinodimethane. Instead, the reaction starts from intermolecular Diels-Alder reactions between DMAD and the furan moiety of vinylphenylfuran, followed by unexpected intramolecular alkene-alkene coupling. This step generates a diradical species, which then undergoes [1,3]-H shift to give the experimentally observed expoxyphenanthrene. DFT calculations revealed that, the [8 + 2] cycloadduct cannot be obtained because the [1,5]-H shift process from the [1,5]-vinyl shift intermediate is disfavored kinetically compared to the [1,3]-H shift to the [8 + 2] isomer.
- Chen, Kai,Wu, Feng,Ye, Lijuan,Tian, Zi-You,Yu, Zhi-Xiang,Zhu, Shifa
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p. 8155 - 8168
(2016/09/28)
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- Oxidative trifluoromethylation and fluoroolefination of unactivated olefins
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Fluorine-containing organic compounds are gaining increasing importance in medicinal chemistry. Described herein is a mild and efficient method for the radical addition of olefins with TMSCF3 and TMSCF2R (R = COOEt or CF3) to deliver various α-trifluoromethylated ketones and α-fluoroolefinated ketones.
- Wu, Ye-Bin,Lu, Guo-Ping,Yuan, Tao,Xu, Zhu-Bing,Wan, Li,Cai, Chun
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supporting information
p. 13668 - 13670
(2016/11/29)
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- Wittig Reactions of Trialkylphosphine-derived Ylides: New Directions and Applications in Organic Synthesis
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The development of semi-stabilized, stabilized, and functionalized ylides derived from short-chain trialkylphosphines in the Wittig-type olefination reactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy separation of water-soluble phosphine oxides. The development of a mild organocatalytic process for the Wittig reaction and extension toward the preparation of reporter stilbenes under biological conditions are also described. Applications toward the preparation of biologically active natural products and derivatives are discussed.
- McNulty, James,McLeod, David,Das, Priyabrata,Zepeda-Velázquez, Carlos
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p. 619 - 632
(2016/01/15)
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- Heck, Sonogashira, and Hiyama reactions catalyzed by palladium nanoparticles stabilized by tris-imidazolium salt
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Palladium nanoparticles, prepared by the hydrogenation of Pd(dba) 2 in the presence of a tris-imidazolium iodide as stabilizer, act as an efficient catalyst for Heck and copper-free Sonogashira reactions with a range of aryl iodides and bromides at 0.2 mol-% Pd loading. Moreover, we describe a convenient protocol for the fluoride-free Hiyama coupling of vinylsilanes with aryl iodides that involves the use of sodium hydroxide as promoter in a methanol/water mixture. Under the developed conditions, one-pot, double Heck and Hiyama-Heck reactions are successfully achieved.
- Planellas, Marc,Moglie, Yanina,Alonso, Francisco,Yus, Miguel,Pleixats, Roser,Shafir, Alexandr
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supporting information
p. 3001 - 3008
(2014/05/20)
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- Cleavage of C-C and C-Si σ-bonds and their intramolecular exchange
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C-C and C-Si σ-bonds are cleaved to undergo bond exchange when substrates equipped with cyclobutanone and silacyclobutane moieties are treated with a palladium(0) catalyst. The skeletal exchange results in construction of silabicyclo[5.2.1]decanes in a diastereoselective manner.
- Ishida, Naoki,Ikemoto, Wataru,Murakami, Masahiro
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supporting information
p. 5912 - 5915
(2014/05/20)
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- SINGLE STEP ENANTIOSELECTIVE PROCESS FOR THE PREPARATION OF 3-SUBSTITUTED CHIRAL PHTHALIDES
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The present invention discloses single step, highly enantioselective catalytic oxidative cyclization process for the synthesis of 3-substituted chiral phthalides. In particular, the invention discloses asymmetric synthesis of chiral phthalides via synergetic nitrile accelerated oxidative cyclization of o-cyano substituted aryl alkenes in high yield and enantiomeric excess (ee) in short reaction time. Also, disclosed herein is “one-pot” asymmetric synthesis of biologically important natural compounds having 3-substituted chiral phthalide structural framework in the molecule.
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Paragraph 0099; 0122; 0123; 0124
(2014/11/13)
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- Mechanistic studies of hoveyda-grubbs metathesis catalysts bearing S-, Br-, I-, and N-coordinating naphthalene ligands
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Derivatives of the Hoveyda-Grubbs complex bearing S-, Br-, I-, and N-coordinating naphthalene ligands were synthesized and characterized with NMR and X-ray studies. Depending on the arrangement of the coordinating sites on the naphthalene core, the isomeric catalysts differ in activity in model metathesis reactions. In particular, complexes with the Rui£CH bond adjacent to the second aromatic ring of the ligand suffer from difficulties experienced on their preparation and initiation. The behavior most probably derives from steric hindrance around the double bond and repulsive intraligand interactions, which result in abnormal chemical shifts of benzylidene protons observed with 1HNMR. Furthermore EXSY studies revealed that the halogen-chelated ruthenium complexes display an equilibrium, in which major cis-Cl2 structures are accompanied with small amounts of isomeric forms. In general, contents of the minor forms, measured at 80°C, correlate with the observed activity trends of the catalysts, although some exceptions complicate the mechanistic picture. We assume that for the family of halogen-chelated metathesis catalysts the initiation mechanism starts with the cis-Cl 2a?trans-Cl2 isomerization, although further steps may become rate-limiting for selected systems. Isomerization first: A family of halogen-chelated Hoveyda-Grubbs complexes displays a cis-Cl2a?trans-Cl2 equilibrium in solution. Relative contents of the minor trans forms go along with the activity of the metathesis catalysts, suggesting its participation in the initiation mechanism (see figure). A unique effect of the naphthalene ligands enables control of the activity over a broad range, from moderately achieve to dormant, and was manifested in 1HNMR for complexes with repulsive H×××H intraligand interactions (Mes=Mesityl).
- Grudzien, Krzysztof,Zukowska, Karolina,Malinska, Maura,Wozniak, Krzysztof,Barbasiewicz, Michal
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supporting information
p. 2819 - 2828
(2014/03/21)
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- Copper-mediated/catalyzed oxyalkylation of alkenes with alkylnitriles
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A copper-promoted oxyalkylation of alkenes with alkylnitriles has been developed. The protocol provides rapid access to phthalides (γ-lactones) or isochromanones (d-lactones) via the formation of a C(sp3)-C(sp3) and a C(sp3)-O bond with the generation of up to two quaternary carbon atoms. Mechanistic studies suggest that this reaction is initiated by the formation of the C(sp3)-C(sp3) bond rather than the C(sp3)-O bond. Catalytic conditions were subsequently developed using carboxylic acid as an internal nucleophile.
- Bunescu, Ala,Wang, Qian,Zhu, Jieping
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supporting information
p. 14633 - 14636
(2015/01/09)
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- Syntheses of 3,4-benzotropolones by ring-closing metatheses
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Ortho-lithiated styrenes or ortho-lithiated benzaldehyde dimethyl acetals were added to 2,2-dimethoxypent-4-enals 7. The resulting alcohols were carried on to the aromatic dienones 10. These were ring-closed by olefin metathesis. Hydrolysis of the dimethyl ketal moiety and enolization provided the 3,4-benzotropolones 5. Overall, this access comprises 4-6 steps and totaled a 22-81% yield.
- Arican, Deniz,Brückner, Reinhard
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supporting information
p. 2582 - 2585
(2013/07/19)
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- A SINGLE STEP ENANTIOSELECTIVE PROCESS FOR THE PREPARATION OF 3-SUBSTITUTED CHIRAL PHTHALIDES
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The present invention discloses single step, highly enantioselective catalytic oxidative cyclization process for the synthesis of 3-substituted chiral phthalides. In particular, the invention discloses asymmetric synthesis of chiral phthalides via synergetic nitrile accelerated oxidative cyclization of o-cyano substituted aryl alkenes in high yield and enantiomeric excess (ee) in short reaction time. Also, disclosed herein is "one -pot" asymmetric synthesis of biologically important natural compounds having 3-substituted chiral phthalide structural framework in the molecule.
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Page/Page column 25; 26
(2013/06/05)
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