- Rhodium-Catalyzed C?H Activation/Annulation Cascade of Aryl Oximes and Propargyl Alcohols to Isoquinoline N-Oxides
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A β-hydroxy elimination instead of common oxidization to carbonyl group in secondary propargyl alcohols was successfully developed to form 2-benzyl substituted isoquinoline N-oxides by a Rhodium-catalyzed C?H activation and annulation cascade, in which moderate to excellent yields (up to 92%) could be obtained under mild reaction conditions, along with good regioselectivity, broad generality and applicability. (Figure presented.).
- Li, Yuan,Fang, Feifei,Zhou, Jianhui,Li, Jiyuan,Wang, Run,Liu, Hong,Zhou, Yu
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supporting information
p. 3305 - 3310
(2021/05/17)
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- Highly Chemo- And Enantioselective Rh-Catalyzed Hydrogenation of β-Sulfonyl-α,β-unsaturated Ketones: Access to Chiral γ-Ketosulfones
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Rh-catalyzed highly chemo- and enantioselective hydrogenation of β-sulfonyl-α,β-unsaturated ketones was first successfully developed. Remarkably, a variety of enantioenriched γ-ketosulfones were generated in good to high yields with excellent chemo/enantioselectivities (82-99% yields, >99:1 chemoselectivity, 88 to >99% ee). Moreover, the gram-scale asymmetric hydrogenation was carried out smoothly in 97% yield and 97% ee. Preliminary DFT computations furnished a reasonable explanation for the high chemoselectivity and enantioselectivity.
- Liu, Gang,Yin, Congcong,Yang, Xuanliang,Li, Anqi,Wang, Minyan,Zhang, Xumu,Dong, Xiu-Qin
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supporting information
p. 19 - 24
(2021/01/13)
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- Laccase-mediated Oxidations of Propargylic Alcohols. Application in the Deracemization of 1-arylprop-2-yn-1-ols in Combination with Alcohol Dehydrogenases
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The catalytic system composed by the laccase from Trametes versicolor and the oxy-radical TEMPO has been successfully applied in the sustainable oxidation of fourteen propargylic alcohols. The corresponding propargylic ketones were obtained in most cases in quantitative conversions (87–>99 % yield), demonstrating the efficiency of the chemoenzymatic methodology in comparison with traditional chemical oxidants, which usually lead to problems associated with the formation of by-products. Also, the stereoselective reduction of propargylic ketones was studied using alcohol dehydrogenases such as the one from Ralstonia species overexpressed in E. coli or the commercially available evo-1.1.200, allowing the access to both alcohol enantiomers mostly with complete conversions and variable selectivities depending on the aromatic pattern substitution (97–>99 % ee). To demonstrate the compatibility of the laccase-mediated oxidation and the alcohol dehydrogenase-catalyzed bioreduction, a deracemization strategy starting from the racemic compounds was developed through a sequential one-pot two-step process, obtaining a selection of (S)- or (R)-1-arylprop-2-yn-1-ols with excellent yields (>98 %) and selectivities (>98 % ee) depending on the alcohol dehydrogenase employed.
- González-Granda, Sergio,Méndez-Sánchez, Daniel,Lavandera, Iván,Gotor-Fernández, Vicente
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p. 520 - 527
(2019/11/16)
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- Gold(iii)-catalyzed azide-yne cyclization/O-H insertion cascade reaction for the expeditious construction of 3-alkoxy-4-quinolinone frameworks
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A gold-catalyzed 6-endo-digazide-yne cyclization/O-H insertion cascade reaction of azide-tethered alkynes with alcohols has been developed, and it provides an expeditious access to 3-alkoxy-4-quinoline derivatives in good to high yields under mild and neutral reaction conditions with broad substrate generality. The utility of this method is emphasized by a scalable experiment and concise total synthesis of a bioactive natural product Leiokinine A, and other bioactive quinoline analogs.
- Bao, Ming,Huang, Jingjing,Qiu, Lihua,Su, Han,Xu, Xinfang,Zhang, Yuanqing
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supporting information
p. 3888 - 3892
(2020/06/03)
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- Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross-Linking
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The design of covalent adaptable networks (CANs) relies on the ability to trigger the rearrangement of bonds within a polymer network. Simple activated alkynes are now used as versatile reversible cross-linkers for thiols. The click-like thiol–yne cross-linking reaction readily enables network synthesis from polythiols through a double Michael addition with a reversible and tunable second addition step. The resulting thioacetal cross-linking moieties are robust but dynamic linkages. A series of different activated alkynes have been synthesized and systematically probed for their ability to produce dynamic thioacetal linkages, both in kinetic studies of small molecule models, as well as in stress relaxation and creep measurements on thiol–yne-based CANs. The results are further rationalized by DFT calculations, showing that the bond exchange rates can be significantly influenced by the choice of the activated alkyne cross-linker.
- Du Prez, Filip E.,Guerre, Marc,Maes, Diederick,Unal, Kamil,Van Herck, Niels,Winne, Johan M.
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supporting information
p. 3609 - 3617
(2020/02/04)
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- Transition-Metal-Free Ring Expansion Reactions of Indene-1,3-dione: Synthesis of Functionalized Benzoannulated Seven-Membered Ring Compounds
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A novel ring expansion reaction of indene-1,3-dione with alkynyl ketones under transition-metal-free conditions has been developed. This process offers an efficient and direct way to synthesize benzoannulated seven-membered rings or fused-ring compounds t
- Yao, Qiyi,Kong, Lingkai,Wang, Mengdan,Yuan, Yang,Sun, Ruizhuo,Li, Yanzhong
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supporting information
p. 1744 - 1747
(2018/04/14)
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- A general two-step one-pot synthesis process of ynones from α-keto acids and 1-iodoalkynes
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A general two-step one-pot synthesis process of ynones was developed by cycloaddition of α-keto acids and 1-iodoalkynes followed by a ring-opening reaction. Its easy conditions and novel mechanism endowed it with two distinctive advantages: iodine-atom bonded to C(sp2) remained intact and α-keto acids became a part of the triple bonds in ynones.
- Zeng, Xiaobao,Liu, Chulong,Yang, Weiguang,Wang, Xingyong,Wang, Xinyan,Hu, Yuefei
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supporting information
p. 9517 - 9520
(2018/08/28)
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- Functionalization of the "bay Region" of Perylene in Reaction with 1-Arylalk-2-yn-1-ones Catalyzed by Trifluoromethanesulfonic Acid: One-Step Approach to 1-Acyl-2-alkylbenzo[ ghi]perylenes
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We describe a convenient method of the synthesis of 1-acyl-2-alkylbenzo[ghi]perylenes via functionalization of the "bay region" of perylene in the reaction with 1-arylalk-2-yn-1-ones catalyzed by trifluoromethanesulfonic acid. We showed that the formation
- G?odek, Marta,Makal, Anna,Plazuk, Damian
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p. 14165 - 14174
(2018/11/23)
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- PROCESS FOR PRODUCING ALKYNYLKETONE DERIVATIVE
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The present invention relates to a Sonogashira-Carbonylation reaction using two types of gas, as well as novel crystals which can control a heat of the said reaction and the process of producing the same. In addition, the present invention relates to a li
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Paragraph 0250; 0251; 0252; 0253
(2017/08/01)
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- Oxyboration with and without a Catalyst: Borylated Isoxazoles via B-O-Bond Addition
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Herein we report an oxyboration reaction with activated substrates that employs B-O σ bond additions to C-C π bonds to form borylated isoxazoles, which are potential building blocks for drug discovery. Although this reaction can be effectively catalyzed by gold, it is the first example of uncatalyzed oxyboration of C-C π bonds by B-O σ bonds-and only the second example that is catalyzed. This oxyboration reaction is tolerant of groups incompatible with alternative lithiation/borylation and palladium-catalyzed C-H activation/borylation technologies for the synthesis of borylated isoxazoles.
- Tu, Kim N.,Hirner, Joshua J.,Blum, Suzanne A.
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supporting information
p. 480 - 483
(2016/02/18)
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- Iron-catalyzed synthesis of β-chlorovinyl and α,β-alkynyl ketones from terminal and silylated alkynes with acid chlorides
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A simple efficient method for the iron(III)-catalyzed synthesis of substituted β-chlorovinyl ketones and α,β-alkynyl ketones from terminal and silyl-substituted alkynes with acid chlorides, respectively, is described. This method features easily available
- Gandeepan, Parthasarathy,Parthasarathy, Kanniyappan,Su, Tsu-Hui,Cheng, Chien-Hong
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experimental part
p. 457 - 468
(2012/04/05)
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- Reaction of frustrated lewis pairs with conjugated ynones-selective hydrogenation of the carbon-carbon triple bond
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Frustrated, but not frustrating: Frustrated Lewis pairs (FLPs) can undergo selective 1,4-addition reactions with conjugated ynones (see scheme). Upon FLP dihydrogen activation selective hydrogenation of the carbon-carbon triple bond can be achieved, in one case even catalytically. Copyright
- Xu, Bao-Hua,Kehr, Gerald,Froehlich, Roland,Wibbeling, Birgit,Schirmer, Birgitta,Grimme, Stefan,Erker, Gerhard
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supporting information; experimental part
p. 7183 - 7186
(2011/09/30)
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- Catalytic enantioselective construction of β-quaternary carbons via a conjugate addition of cyanide to β,β-disubstituted α,β-unsaturated carbonyl compounds
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The first general catalytic enantioselective conjugate addition of cyanide to β, β-disubstituted α,β-unsaturated ketones and N-acylpyrroles was developed using a strontium catalyst derived from Sr(O iPr)2 and new chiral ligand 5. The reaction exhibited excellent enantioselectivity and a wide substrate scope using 0.5-10 mol % catalyst. 1,4-Adducts containing β-quaternary carbons were exclusively produced over 1,2-adducts. ESI-MS analysis of the strontium catalyst indicated that the active catalyst was a trimetallic Sr/5 = 3:5 complex. The exclusive 1,4-selectivity was partly due to the ability of the strontium complex to promote both a retro-cyanation reaction from the 1,2-adducts and highly enantioselective conjugate cyanation.
- Tanaka, Yuta,Kanai, Motomu,Shibasaki, Masakatsu
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supporting information; experimental part
p. 8862 - 8863
(2010/08/21)
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- Two-step synthesis of β-alkyl chalcones and their use in the synthesis of 3,5-diaryl-5-alkyl-4,5-dihydropyrazoles
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We report a simple and efficient two-step synthesis of variously substituted β-alkyl chalcones (7) from the corresponding Weinreb amide and a terminal alkyne, and that these chalcones are useful intermediates for the synthesis of medicinally interesting 3,5-diaryl-5-alkyl-4,5-dihydropyrazoles (6). The current methodology allows for the incorporation of many substitution patterns not available from the few previously reported approaches to compounds in this class.
- Cox, Christopher D.,Breslin, Michael J.,Mariano, Brenda J.
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p. 1489 - 1493
(2007/10/03)
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- A general and efficient PIFA mediated synthesis of heterocycle-fused quinolinone derivatives
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A new application of the hypervalent iodine reagent phenyliodine(III)bis(trifluoroacetate) (PIFA) has been developed for the construction of a series of N, O, S-containing heterocycle-fused quinolinone derivatives in a general and efficient way. An altern
- Herrero, M.Teresa,Tellitu, Imanol,Domínguez, Esther,Hernández, Susana,Moreno, Isabel,SanMartín, Raúl
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p. 8581 - 8589
(2007/10/03)
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- The reaction of 2-(tetrazol-5-yl)alkyl ketones and of 2-(tetrazol-5-yl)alkanoic acid derivatives with lead tetraacetate. A novel method of preparation of alk-2-ynyl ketones and alk-2-ynoic acid derivatives
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The majority of tetrazolylacetyl derivatives 2 and 7, when treated with lead tetraacetate in dry 1,4-dioxane at room or lower temperature, are oxidized with elimination of molecular nitrogen mainly to the corresponding alkynoyl derivatives 4 and 8, respectively. Vinylidenes (25) have been shown to be the intermediates of the reaction. The reaction does not take place when either the tetrazolyl group is N-substituted or the carbon atom separating the tetrazolyl and the carbonyl groups is disubstituted or these two groups are separated by two carbon atoms as in compound 17. The reaction offers a convenient method for the conversion of 2-cyanoacetyl derivatives into alk-2-ynoyl derivatives via intermediate tetrazolylacetyl derivatives. The 4-methoxyanilide 7o reacts differently, affording the fused heterocyclic compounds 19o and 20o.
- Fetter,Nagy,Giang,Kajtar-Peredy,Rockenbauer,Korecz,Czira
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p. 1131 - 1139
(2007/10/03)
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- A New General Synthesis of 2,2-Dialkyl-2,3-dihydro-4H-pyran-4-ones and Their Application for the in situ Preparation of Electron-Rich Dienes in Carbonyl-Alkyne Exchange Reactions with Acetylenes
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The substituted 2,2-dialkyl-2,3-dihydro-4H-pyran-4-ones of type II and III have been prepared by acid-catalyzed cyclization of the corresponding substituted acetylenic ketones I in good to excellent yields (Scheme 1).These 2,2-dialkyl-2,3-dihydro-4H-pyran
- Obrecht, Daniel
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- Facile Dehydration of Activated Ketones to Alkynes
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Ketones activated by β-carbonyl or phenyl groups are readily dehydrated to alkynes with (PhP(1+))2O, 2OTf(1-) and triethylamine in refluxing 1,2-dichloroethane.
- Hendrickson, James B.,Hussoin, Md. Sajjat
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p. 217 - 218
(2007/10/02)
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- Efficient methods for the preparation of acetylenic ketones
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A number of acetylenic ketones RCCC(=O)R' have been obtained in good yields from lithiated acetylenes RCCLi and acetic anhydride, N,N-dimethylacetamide, or N,N-dimethylbenzamide.The most convenient and general method consists of treating alkynylzinc chlorides with acid halides R'C(=O)Cl.Benzoyl chloride (R'=Ph), acryloyl chloride (R'=CH2=CH) and butynoyl chloride (R'=C2H5CC) react only in the presence of a catalytic amount of Pd4.
- Verkruijsse, H. D.,Heus-Kloos, Y. A.,Brandsma, I.
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p. 289 - 294
(2007/10/02)
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- Reaction of Triphenylphosphine Radical Cation with 1,3-Dicarbonyl Compounds: Electrochemical One-Step Preparation of Dioxomethylenetriphenylphosphoranes
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Electrochemical oxidation of Ph3P (1) in MeCN in the presence of 1,3-dicarbonyl compounds, R1COCH2COR2 (3), with HClO4 as the supporting electrolyte resulted in the formation of the phosphonium salts, Ph3P+ -CH(COR1)COR2 ClO4- (4), provided that R1 and/or R2 is a phenyl group.On the other hand, electrolysis in CH2Cl2 with 2,6-lutidinium perchlorate gave the phosphoranes, Ph3P=C(COR1)COR2 (5), directly from 1 and 3 in fair to excellent yields: in this case, R1 or R2 need not necessarily be a phenyl group.Thus, the electrolysis is shown to be a convenient method to prepare 5 in a single step.Plausible processes for the formation of 4 and 5 are proposed, involving the reaction of electrochemically generated Ph3P+. with the enol form of 3 as the keystep.Keywords - triphenylphosphine; 1,3-dicarbonyl compound; dioxomethyltriphenylphosphonium perchlorate; dioxomethylenetriphenylphosphorane; electrochemical oxidation; constant current electrolysis
- Ohmori, Hidenobu,Maeda, Hatsuo,Tamaoka, Mie,Masui, Masaichiro
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p. 613 - 620
(2007/10/02)
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- A Case of Highly Diastereoselective Addition to Unsymmetrical Ketones: lk-Addition of (2-Alkenyl)triphenoxytitanium Derivatives
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(2-Butenyl)-, (4-methyl-2-pentenyl)-, and (2-heptenyl)triphenoxytitanium (2a-c) add to dialkyl, alkyl aryl-, and alkinyl aryl ketones to give high yields of tertiary homoallylic alcohols (5-12), which are diastereomerically enriched up to 98percent.Config
- Seebach, Dieter,Widler, Leo
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p. 1972 - 1981
(2007/10/02)
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