An unprecedented strategy to access highly enantioenriched dihydropyrazoles is described. It involves formal [4+1] cycloadditions of in situ-derived azoalkenes and sulfurylides catalyzed by a chiral copper/Tol-BINAP complex. A variety of synthetically and biologically important dihydropyrazoles have been obtained with high enantioselectivities (up to 97:3 er) in good yields (83-97%).
Substrate-controlled reactions have been developed for the synthesis of spirocyclopropylpyrazolones and bicyclic 4,5-dihydropyrazoles from 1,2-diaza-1,3-dienes and sulfur ylides. These protocols were carried out under mild reaction conditions without any additives in generally moderate to good yields. Plausible mechanisms for the transformations were proposed.
作者:Cong Ye、Bao-Gui Cai、Juan Lu、Xiao Cheng、Lei Li、Zhong-Wen Pan、Jun Xuan
DOI:10.1021/acs.joc.0c02500
日期:2021.1.1
A blue-light-emitting diode (LED) promoted coupling of aryl diazoacetates with sulfurylides is described. This protocol features mild conditions, good functional group tolerance, and broad substrate scope for both aryl diazoacetates with sulfurylides. Under optimal reaction conditions, a wide range of trisubstituted olefins is obtained in moderate to good yield, which can be further transferred to
Visible-Light-Driven Radical Multicomponent Reaction of 2-Vinylanilines, Sulfonyl Chlorides, and Sulfur Ylides for Synthesis of Indolines
作者:Mukund M. D. Pramanik、Fan Yuan、Dong-Mei Yan、Wen-Jing Xiao、Jia-Rong Chen
DOI:10.1021/acs.orglett.0c00602
日期:2020.4.3
A visible-light-driven photoredox-catalyzed multicomponent reaction of 2-vinylanilines, sulfonyl chlorides, and sulfur ylides is described. This protocol features redox-neutral mild conditions, a broad substrate scope, and good functional group tolerance, providing access to various sulfonated 2,3-disubstituted indolines. The product can be transformed to a diverse range of functionalized indoles by
Synthesis of Functionalized Thietanes via Electrophilic Carbenoid-Induced Ring Expansion of Thiiranes with Sulfonium Acylmethylides as Carbene Precursors
作者:Jun Dong、Hongguang Du、Jiaxi Xu
DOI:10.1021/acs.joc.9b01152
日期:2019.9.6
Various functionalized thietanes were prepared from thiiranes via an electrophilic ring expansion with rhodium carbenoids as electrophiles generated from safe and readily accessible dimethylsulfonium acylmethylides. The reaction appears to proceed through electrophilic metallocarbenoid-induced activation of thiiranes, nucleophilic ring-opening of the activated thiiranes with dimethyl sulfide as a transient