202914-74-7Relevant academic research and scientific papers
Metal-Free Radical Annulation of Oxygen-Containing 1,7-Enynes: Configuration-Selective Synthesis of (E)-3-((Arylsulfonyl)methyl)-4-Substituted Arylidenechromene Derivatives
Bian, Mouwang,Dai, Lei,Mao, Kaimin,Rong, Liangce,Wang, Chang,Yu, Qiuyu,Zhang, Jinghang
supporting information, p. 218 - 224 (2021/01/13)
A novel strategy for the synthesis of (E)-3-((arylsulfonyl)methyl)-4-substituted benzylidenechromene derivatives via a metal-free radical annulation reaction of oxygen-containing 1,7-enynes with thiosulfonates has been developed. The reaction shows broad substrate scope, wide functional group tolerance, and moderate to excellent yields. Moreover, thiosulfonates were well driven to achieve the bifunctionalization reaction of oxo-1,7-enynes which derived from aliphatic alkynes. In addition, the (E)-configuration of the products was highly controlled by the structure of 1,7-enyne.
A Facile Construction of Bisheterocyclic Methane Scaffolds through Palladium-Catalyzed Domino Cyclization
Qi, Hongbo,Han, Kaiming,Chen, Shufeng
supporting information, p. 2699 - 2704 (2021/08/03)
A convenient palladium-catalyzed domino cyclization reaction for the construction of bis(benzofuranyl)methane scaffolds bearing an all-carbon quaternary center has been described. In the cascade process, one C(sp2)—O bond, two C(sp2)—C(sp3) bonds as well as two benzofuran rings are formed in a single synthetic sequence. The approach shows wide scope of substrates and good functional-group tolerance. Moreover, this methodology is successfully extended to the synthesis of benzofuranyl methyl chromane derivatives.
Functionalized Benzofurans via Microwave-Promoted Tandem Claisen-Rearrangement/5-endo-dig Cyclization
Schultze, Christiane,Schmidt, Bernd
, p. 2619 - 2629 (2019/08/22)
Ortho-allyloxy alkinyl benzenes undergo, upon microwave irradiation in dimethylformamide, a tandem sequence of Claisen-rearrangement and 5-endo-dig cyclization to furnish 7-allyl-substituted benzofurans. With terminal alkynes, chroman-4-ones and enaminoketones become the main products. A mechanistic proposal for this observation relies on a reaction of the starting material with the solvent dimethylformamide under the microwave conditions.
Metal-free difunctionalization of alkynes to access tetrasubstituted olefins through spontaneous selenosulfonylation of vinylidene: Ortho -quinone methide (VQM)
Huang, Shengli,Chen, Zhili,Mao, Hui,Hu, Fangli,Li, Dongmei,Tan, Yu,Yang, Fengqing,Qin, Wenling
supporting information, p. 1121 - 1129 (2019/02/07)
A metal-free difunctionalization of alkynes to access tetrasubstituted olefins through spontaneous selenosulfonylation of vinylidene ortho-quinone methide (VQM) was described herein. The reaction was conducted under mild conditions without any catalysts or additives. Preliminary mechanism studies revealed that the formation of VQM was the key for this alkyne di-functionalization reaction. The reaction could be applied in the enantioselective asymmetric synthesis of axially chiral styrene. Furthermore, the selenosulfonylation adducts can be transformed into useful naphtho[2,1-b]furan and benzofuran scaffolds.
Light-Induced Mechanistic Divergence in Gold(I) Catalysis: Revisiting the Reactivity of Diazonium Salts
Taschinski, Svenja,D?pp, René,Ackermann, Martin,Rominger, Frank,de Vries, Folkert,Menger, Maximilian F. S. J.,Rudolph, Matthias,Hashmi, A. Stephen K.,Klein, Johannes E. M. N.
supporting information, p. 16988 - 16993 (2019/11/13)
In a systematic study of the Au-catalyzed reaction of o-alkynylphenols with aryldiazonium salts, we find that essentially the same reaction conditions lead to a change in mechanism when a light source is applied. If the reaction is carried out at room temperature using a AuI catalyst, the diazonium salt undergoes electrophilic deauration of a vinyl AuI intermediate and provides access to substituted azobenzofurans. If the reaction mixture is irradiated with blue LED light, C?C bond formation due to N2-extrusion from the diazonium salt is realized selectively, using the same starting materials without the need for an additional photo(redox) catalyst under aerobic conditions. We report a series of experiments demonstrating that the same vinyl AuI intermediate is capable of producing the observed products under photolytic and thermal conditions. The finding that a vinyl AuI complex can directly, without the need for an additional photo(redox) catalyst, result in C?C bond formation under photolytic conditions is contrary to the proposed mechanistic pathways suggested in the literature till date and highlights that the role of oxidation state changes in photoredox catalysis involving Au is thus far only poorly understood and may hold surprises for the future. Computational results indicate that photochemical activation can occur directly from a donor–acceptor complex formed between the vinyl AuI intermediate and the diazonium salt.
One-pot synthesis of 2,3-disubstituted benzofurans from 2-chlorophenols using palladium–dihydroxyterphenylphosphine catalyst
Yamaguchi, Miyuki,Ozawa, Hayato,Katsumata, Haruka,Akiyama, Tomoyo,Manabe, Kei
supporting information, p. 3175 - 3178 (2018/07/15)
2,3-Disubstituted benzofurans possessing 2-hydroxyphenyl moiety at the C-3 position were synthesized from readily available 2-chlorophenols and terminal alkynes by hydroxy-directed ortho-Sonogashira coupling and subsequent oxypalladation/reductive elimina
Enantioselective intramolecular cyclization of alkynyl esters catalyzed by a chiral Br?nsted base
Kondoh, Azusa,Tran, Hoa Thi Quynh,Kimura, Kyoko,Terada, Masahiro
, p. 5726 - 5729 (2016/05/19)
An enantioselective intramolecular cyclization reaction of alkynyl esters was developed, which employs a Br?nsted base catalyst generated in situ from a chiral Schiff base and t-BuOK. This reaction is a rare example of the enantioselective intramolecular addition of simple ester enolates to alkynes under Br?nsted base catalysis.
Dual Photoredox/Gold Catalysis Arylative Cyclization of o-Alkynylphenols with Aryldiazonium Salts: A Flexible Synthesis of Benzofurans
Xia, Zhonghua,Khaled, Omar,Mouriès-Mansuy, Virginie,Ollivier, Cyril,Fensterbank, Louis
, p. 7182 - 7190 (2016/08/30)
A new method for the arylative cyclization of o-alkynylphenols with aryldiazonium salts via dual photoredox/gold catalysis is described. The reaction proceeds smoothly at room temperature in the absence of base and/or additives and offers an efficient app
A concise approach for the synthesis of 3-iodoindoles and 3-iodobenzo[b]furans via Ph3P-catalyzed iodocyclization
Li, Yin-Long,Li, Jian,Yu, Sheng-Nan,Wang, Ji-Bo,Yu, Yan-Min,Deng, Jun
supporting information, p. 8271 - 8277 (2015/10/05)
A variety of 3-iodoindole and 3-iodobenzo[b]furan derivatives were conveniently prepared from the corresponding 2-alkynylanilines and 2-alkynylphenols through Ph3P-catalyzed iodocyclization in the presence of N-iodosuccinimide (NIS). This proto
Efficient microwave-assisted one-pot three-component synthesis of 2,3-disubstituted benzofurans under Sonogashira conditions
Markina, Nataliya A.,Chen, Yu,Larock, Richard C.
, p. 2701 - 2713 (2013/03/28)
An efficient one-pot method for the synthesis of 2,3-disubstituted benzo[b]furans from commercially available 2-iodophenols, terminal acetylenes and aryl iodides has been developed utilizing Sonogashira reaction conditions. After an initial Sonogashira coupling of the 2-iodophenol with the terminal alkyne, cyclization involving the aryl iodide provides the 2,3-disubstituted benzo[b]furan in good to excellent yields. The use of microwave irradiation shortens the reaction times and minimizes the side products. This methodology is especially useful for the construction of libraries of highly substituted benzo[b]furans and their analogues.
