- A chemo- And regioselective Pd(0)-catalyzed three-component spiroannulation
-
A chemo- and regioselective Pd(0)-catalyzed spiroannulation has been successfully developed. The key feature of this method is the use of readily available 1,2-dihaloarenes, alkynes and 2-naphthols for the rapid assembly of spirocarbocyclic molecules. Mechanistic studies revealed that this domino reaction proceeded through a cascade of oxidative addition to Pd(0), alkyne migratory insertion, and 2-naphthol-facilitated dearomatizing [4+1] spiroannulation.
- Wu, Jiaoyu,Bai, Lu,Han, Lingbo,Liu, Jingjing,Luan, Xinjun
-
-
Read Online
- Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
-
The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
- Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
-
supporting information
p. 16470 - 16485
(2021/10/20)
-
- Helicene synthesis by Br?nsted acid-catalyzed cycloaromatization in HFIP [(CF3)2CHOH]
-
A facile synthesis of carbo- and heterohelicenes was achieved via tandem cycloaromatization of bisacetal precursors, which were readily prepared through C-C bond formation by Suzuki-Miyaura coupling. This cyclization was efficiently realized by a catalytic amount of trifluoromethanesulfonic acid (TfOH) in a cation-stabilizing solvent, 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP), which readily allowed gram-scale syntheses of higher-order helicenes, double helical helicenes, and heterohelicenes.
- Fujita, Takeshi,Shoji, Noriaki,Yoshikawa, Nao,Ichikawa, Junji
-
p. 396 - 403
(2021/03/20)
-
- Pd-Catalyzed Denitrative Intramolecular C-H Arylation
-
A Pd-catalyzed intramolecular C-H arylation of nitroarenes has been developed. Nitroarenes bearing tethered aryl groups at the ortho-position can be readily prepared in one step from 2-halonitroarenes by a nucleophilic aromatic substitution (SNAr). Under Pd/BrettPhos catalysis, activations of the C-NO2 bond as well as the C-H bond on arenes generated the corresponding biaryl linkage in moderate to excellent yields.
- Asahara, Kitty K.,Okita, Toshimasa,Saito, Ami N.,Muto, Kei,Nakao, Yoshiaki,Yamaguchi, Junichiro
-
supporting information
p. 4721 - 4724
(2019/06/17)
-
- Naphthylbenzofuran derivative and preparation method thereof
-
The invention belongs to the technical field of organic synthesis and particularly relates to a naphthylbenzofuran derivative and a preparation method thereof. The preparation method comprises that a1-bromo-2-naphthol derivative and a phenylboronic acid derivative undergo a reaction to produce an intermediate, the intermediate undergoes an intramolecular dehydration and ring-forming reaction under the action of cesium carbonate to produce the naphthylbenzofuran derivative. The naphthylbenzofuran and its derivative can be used as important synthesis intermediates of functional organic semiconductors such as organic electroluminescence devices, organic solar batteries, organic lasers, optical switches and ion detectors. The modified compound can be used as light-emitting host and guest materials, a carrier transport material and an exciton-blocking material in organic electroluminescent devices. The invention can provide the naphthylbenzofuran derivative with the advantages of simple processes, low synthesis condition requirements, high synthesis yield, industrial large-scale production feasibility and good economic benefits and the preparation method thereof.
- -
-
Paragraph 0028; 0030
(2018/07/06)
-
- Regioselective Synthesis of Polycyclic and Heptagon-embedded Aromatic Compounds through a Versatile π-Extension of Aryl Halides
-
A versatile π-extension reaction was developed based on the three-component cross-coupling of aryl halides, 2-haloarylcarboxylic acids, and norbornadiene. The transformation is driven by the direction and subsequent decarboxylation of the carboxyl group, while norbornadiene serves as an ortho-C?H activator and ethylene synthon via a retro-Diels–Alder reaction. Comprehensive DFT calculations were performed to account for the catalytic intermediates.
- Fu, Wai Chung,Wang, Zheng,Chan, Wesley Ting Kwok,Lin, Zhenyang,Kwong, Fuk Yee
-
supporting information
p. 7166 - 7170
(2017/06/13)
-
- Pd(0)-catalyzed chemoselective construction of spirocarbocycles via an alkyne insertion/β-naphthol dearomatization cascade
-
A microwave-assisted Pd(0)-catalyzed alkyne migratory insertion/β-naphthol dearomatization cascade process has been accomplished to access a variety of spirocyclic compounds bearing all-carbon quaternary stereogenic centers in high yields with excellent chemoselectivities.
- Zheng, Huayu,Bai, Lu,Liu, Jingjing,Nan, Jiang,Zuo, Zhijun,Yang, Liu,Wang, Yaoyu,Luan, Xinjun
-
p. 3061 - 3064
(2015/06/08)
-
- One pot synthesis of diarylfurans from aryl esters and PhI(OAc)2 via palladium-associated iodonium ylides
-
The example of palladium-catalyzed intermolecular cyclization for the synthesis of various diarylfurans in which one of the aromatic rings originates from the phenolic part of the starting ester and the other one from PhI(OAc)2 has been reported. The reaction is carried out through two steps: the rearrangement of palladium-associated iodonium ylides to form o-iodo diaryl ether and then palladium catalyzed intramolecular direct arylation. This reaction can tolerate a variety of functional groups and is alternative or complementary to the previous methods for the synthesis of diarylfurans.
- Bao, Yong-Sheng,Bao, Agula,Bao, Zhaorigetu,Jia, Meilin,Baiyin, Menghe
-
supporting information
p. 4179 - 4182
(2015/04/14)
-
- Di-tert-butylneopentylphosphine (DTBNpP): An Efficient Ligand in the Palladium-Catalyzed α-Arylation of Ketones
-
Di-tert-butylneopentylphosphine (DTBNpP) and palladium(II) acetate provide an efficient catalytic system for the α-arylation of ketones. Aryl bromides were coupled with ketones using 0.25-0.5 mol-% Pd(OAc)2/DTBNpP in toluene at 50 C, whereas aryl chlorides required a higher catalyst loading (0.5-2.0 mol-%) and a higher temperature (80 C). Coupling of 2-bromophenol with ketones using the Pd/DTBNpP system provides an efficient route for the synthesis of benzofurans.
- Raders, Steven M.,Jones, Jessica M.,Semmes, Jeffrey G.,Kelley, Steven P.,Rogers, Robin D.,Shaughnessy, Kevin H.
-
p. 7395 - 7404
(2016/02/19)
-
- Experimental NMR and DFT studies of persistent carbocations derived from hetero-polycyclic aromatic hydrocarbons containing oxygen atom: Dibenzo[b,d]furan, Benzo[b]naphtho[1,2-d]furan, Benzo[b]naphtho[2,3-d]furan, Benzo[b]naphtho[2,1-d]furan, and Dinaphtho[2,1-b: 1′,2′-d]furan
-
Persistent protonation carbocations generated from hetero-PAHs containing oxygen atoms in their aromatic rings, dibenzo[b,d]furan (5), benzo[b]naphtho[1,2-d]furan (6), benzo[b]naphtho[2,3-d]furan (7), benzo[b]naphtho[2,1-d]furan (8), and dinaphtho[2,1-b: 1′,2′-d]furan (9), were directly observed by NMR measurements in superacid. Compound 5 was protonated mainly at C(2) in FSO3H-SbF5 (1: 1) or (4: 1)/SO2ClF, and 6, 8, and 9 were protonated exclusively at C(5) in CF3SO3H or FSO3H/SO2ClF, whereas 7 was protonated at C(6) and C(11) to give two species in FSO3H/SO2ClF. Surprisingly, compound 5 resists protonation in FSO3H/SO2ClF to show NMR spectra corresponding to that of the intact material. Positive charge delocalization mapping for carbocations based on experimental Δδ13C values indicates limited delocalization in these systems. The chemical shifts and charge delocalization modes derived by DFT calculations agreed with the experimental results.
- Okazaki, Takao,Nakagawa, Madoka,Kitagawa, Toshikazu,Laali, Kenneth K.
-
p. 1235 - 1244
(2015/02/18)
-
- Palladium-catalyzed intra-and intermolecular C-H arylation using mesylates: Synthetic scope and mechanistic studies
-
This paper describes the development of Pd-catalyzed inter-and intramolecular direct arylation using mesylates. Furthermore, a sequential mesylation/arylation protocol using phenols as substrates is described. These transformations are general with respect to the electronics of the C-H substrates and allow for the synthesis of diverse heterocyclic motifs in good yields. Both arenes and heteroarenes efficiently participate in these reactions. Preliminary mechanistic studies are presented for both inter-and intramolecular arylations.
- Ferguson, Devin M.,Rudolph, Stacey R.,Kalyani, Dipannita
-
p. 2395 - 2401
(2014/07/21)
-
- Nickel-catalyzed intramolecular C-H arylation using aryl pivalates as electrophiles
-
This paper describes a method for nickel catalyzed intramolecular C-H arylation using aryl pivalates as electrophiles. The transformation is efficient for the synthesis of diverse electronically and sterically differentiated dibenzofurans. Additionally, the method could be expanded toward the synthesis of carbazoles. Preliminary mechanistic studies of the transformation are also described.
- Wang, Jiayi,Ferguson, Devin M.,Kalyani, Dipannita
-
p. 5780 - 5790
(2013/07/19)
-
- Rhodium-catalyzed decarbonylative C-H arylation of 2-aryloxybenzoic acids leading to dibenzofuran derivatives
-
Rhodium-catalyzed intramolecular C-H arylation of 2-aryloxybenzoic acids proceeded accompanied by decarbonylation to give dibenzofuran derivatives in high yields. The present reaction is widely applicable to substrates bearing various functionalities.
- Maetani, Shinji,Fukuyama, Takahide,Ryu, Ilhyong
-
supporting information
p. 2754 - 2757
(2013/07/19)
-
- Palladium-catalyzed intramolecular C-H arylation of arenes using tosylates and mesylates as electrophiles
-
This paper describes a method for the palladium catalyzed intramolecular C-H arylation using tosylates and mesylates as electrophiles. The transformation is efficient for the synthesis of various heterocyclic motifs including furans, carbazoles, indoles, and lactams. Additionally, a protocol for the one-pot sequential tosylation/arylation of phenol derivatives is presented.
- Nervig, Christine S.,Waller, Peter J.,Kalyani, Dipannita
-
p. 4838 - 4841,4
(2020/09/16)
-
- Organoboron Compound and Method for Manufacturing the Same
-
To provide a novel organoboron compound which is useful as a reactant of organic synthesis. To provide a method for manufacturing the organoboron compound. A novel organoboron compound represented by General Formula (G1) below is provided. Note that in General Formula (G1), R1 to R9 separately represent any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 16 carbon atoms. R10 and R11 separately represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and R10 and R11 may be bonded with each other to form a ring. Further, X represents an oxygen atom or a sulfur atom.
- -
-
-
- Benzo[b]Naphtho[1,2-d]Furan Compound as Light-Emitting Element Material
-
Provided is a benzo[b]naphtho[1,2-d]furan compound having a wide band gap which gives excellent color purity of blue. Further provided are a light-emitting element, a light-emitting device, and an electronic device each of which uses the benzo[b]naphtho[1,2-d]furan compound and is highly reliable. A benzo[b]naphtho[1,2-d]furan compound represented by a general formula (G1) is provided. In the general formula (G1), An represents an anthryl group represented by a general formula (An-1) or (An-2) below, α1 and α2 separately represent a substituted or unsubstituted phenylene group represented by any one of general formulae (α-1) to (α-3) below, and R1 to R9 separately represent either hydrogen or an alkyl group having 1 to 4 carbon atoms. Further, in the general formula (G1), n and m separately represent 0 or 1.
- -
-
-
- Formation of dibenzofurans by flash vacuum pyrolysis of aryl 2-(allyloxy)benzoates and related reactions
-
Flash vacuum pyrolysis (FVP) of aryl 2-(allyloxy)benzoates 5 and of the corresponding aryl 2-(allylthio)benzoates 6 at 650°C, gives dibenzofurans 19 and dibenzothiophenes 20, respectively. The mechanism involves generation of phenoxyl (or thiophenoxyl) radicals by homolysis of the O-allyl (or S-allyl) bond, followed by ipso attack at the ester group, loss of CO2 and cyclisation of the resulting aryl radical. Synthetically, the procedure works well for p-substituted substrates, which lead to 2-substituted dibenzofurans 19b-f (73-90%) and dibenzothiophenes 20b-c (90-94%). Little selectivity is shown in the cyclisation of m-substituted substrates and competing interactions of the radical with the substituent - and ipso-attack - complicate the pyrolyses of o-substituted substrates. FVP of related radical precursors including 2-(allyloxy)phenyl benzoates 43 gave no dibenzofurans, whereas 2-(allyloxy-5-methyl)azobenzene 44 gave a much reduced yield. No carbazoles were obtained by FVP of 4-methylphenyl 2-(allylamino)benzoate 42.
- Black, Michael,Cadogan,McNab, Hamish
-
experimental part
p. 2961 - 2967
(2010/09/06)
-
- New gas-phase cascade reactions of stabilized phosphorus ylides leading to ring-fused indoles and to quinolines
-
(Chemical Equation Presented) Gas-phase cyclization processes of stabilized phosphorus ylides bearing a suitably substituted 2-aminophenyl group lead efficiently either to 3-substituted quinolines or benzo[c]-carbazole and heterocyclic-fused analogues depending on the substituents present.
- Aitken, R. Alan,Murray, Lorna
-
body text
p. 9781 - 9783
(2009/04/06)
-
- Aryl-aryl bond formation by flash vacuum pyrolysis of benzannulated thiopyrans
-
(Chemical Equation Presented) In contrast to fully unsaturated 7-membered ring sulfur heterocycles (thiepines), some of which extrude sulfur and give the ring-contracted hydrocarbon even at room temperature in solution, benzannulated thiopyrans (6-membere
- Amick, Aaron W.,Wakamiya, Atsushi,Scott, Lawrence T.
-
p. 5119 - 5122
(2008/12/20)
-
- High pressure and thermal Diels-Alder reaction of 2-vinyl-benzo[b]furan and 2-vinyl-benzo[b]thiophene. Synthesis of new condensed heterocycles
-
A new preparation of 2-vinyl-benzo[b]furan and 2-vinyl-benzo[b]thiophene is described. Diels-Alder reactions of these dienes with 3-nitro-2-cyclohexen-1-one and 2-inden-1-one was examined under thermal and high pressure conditions. The reaction products have been converted to multi-ring heteroaromatic compounds.
- Marrocchi, Assunta,Minuti, Lucio,Taticchi, Aldo,Scheeren, Hans W
-
p. 4959 - 4965
(2007/10/03)
-
- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 14. Tandem cyclisation of intermediate aryloxy and arylthio radicals leading to tri- and tetra-cyclic aromatic heterocycles
-
Seven new stabilised phosphorus ylides 8-14 designed to undergo thermal tandem cyclisation have been prepared. Upon flash vacuum pyrolysis at 850°C, loss of Ph3PO and Me? results in tandem cyclisation to give benzothieno[3,2-b]benzothiophene 16 in the case of 11 while for 8 an abstraction-rearrangement-extrusion sequence leads to 2-phenylbenzofuran 18. For 9 and 10 both types of process occur to give respectively benzothieno[3,2-b]benzofuran 27, prepared here for the first time, and 2-phenylbenzothiophene 29. For 12 and 13, initial cyclisation is followed by intramolecular addition and aromatisation to give the tricyclic products 31 and 32, while for 14 intramolecular homolytic substitution leads to the tetracyclic benzonaphthofuran 34 and, by rearrangement, to the isomer 37. Fully assigned 13C NMR spectra are presented for all seven ylides.
- Aitken, R. Alan,Burns, Graham,Morrison, John J.
-
p. 3937 - 3941
(2007/10/03)
-
- Photostimulated Reactions of o-Dihalobenzenes with Nucleophiles Derived from the 2-Naphthyl System. Competition between Electron Transfer, Fragmentation, and Ring Closure Reactions
-
The photostimulated reaction of o-dihalobenzenes 2 with 2-naphthoxide ions 1-O gave the substitution product on carbon 1 of the naphthyl moiety with retention of halogen (I, Br, and Cl) 3 as well as the ring closure product benzonaphtholfuran (4), with product 3 being an intermediate in the formation of 4.The products obtained in the photostimulated reaction of 2-naphthalenethiolate ions 1-S with 2 depend on the halogens.When both nucleofugal groups are iodine, only the ring closure product benzonaphthothiophene (10) is obtained.With o-bromoiodobenzene, the photostimulated reaction gave 10 and the substitution product on sulfur with retention of bromine, while with o-chloroiodobenzene the only observed product was the substitution product on sulfur with retention of chlorine.The photostimulated reaction of 2 with 2-naphthaleneselenolate ions 1-Se gave the same amount of cyclized product benzonaphthoselenophene (14) and the substitution product on selenium without retention of halogen 15, although in an overall low yield.It is suggested that all these reactions occur by the SRN1 mechanism.Theoretical studies support the different behavior found with the nucleophiles derived from the 2-naphthyl system.
- Baumgartner, Maria T.,Pierini, Adriana B.,Rossi, Roberto A.
-
p. 2593 - 2598
(2007/10/02)
-
- The reactivity of oxygen nucleophiles with aryl radicals in the S(RN)1 mechanism
-
The photostimulated reaction of 2-naphthoxide ions 1 with o-dihalobenzenes in liquid ammonia gives the halosubstituted product 4 and the cyclized substituted product 5. This is the first report about the coupling of an aromatic σ radical with an oxygen functionality in the chain propagation cycle of the S(RN)1 mechanism.
- Baumgartner,Pierini,Rossi
-
p. 2323 - 2326
(2007/10/02)
-
- A Short Synthesis of Dibenzofurans and Dibenzothiophenes
-
An afficient synthesis of dibenzofurans and dibenzothiophenes from aryl salicylates is described, which involves a novel rearrangement-extrusion-cyclisation sequence of o-substituted phenoxyl and thiophenoxyl radicals.
- Black, Michael,Cadogan, J. I. G.,McNab, Hamish
-
p. 395 - 396
(2007/10/02)
-