Preparation of chiral cyclopropanes with a carbohydrate fragment from levoglucosenone
作者:Alexander V. Samet、Anatolly M. Shestopalov、Dmitriy N. Lutov、Lyudmila A. Rodinovskaya、Alexander A. Shestopalov、Victor V. Semenov
DOI:10.1016/j.tetasy.2007.08.013
日期:2007.8
Levoglucosenone (a chiral α,β-unsaturated ketone derivative of cellulose) underwent stereoselective cyclopropanation with sulfonium ylides to form chiral trisubstituted cyclopropanes annulated with the carbohydrate moiety in high yields.
A metal-free direct trifluoromethylthiolation of sulfonium ylides with an electrophilic trifluoromethylthiolating reagent has been established, in which sulfonium salt or α-bromoacetic ester is employed as sulfonium ylide precursors. This trifluoromethylthiolation enables the straightforward construction of SCF3-substituted sulfonium ylides from a wide range of substrates, including ketones, esters
Reactions of Sulfonium Salts with 2,3-Dioxopyrrolidine Derivatives: A Concise Synthesis of Spirocyclopropane
作者:Peng-Fei Xu、Shuang Zhang、Xiu-Qin Hu、Zhu-Yin Wang
DOI:10.1055/s-0034-1380522
日期:——
3-dioxopyrrolidine derivatives with sulfoniumsalts is described. This reaction enables a novel concise access to polysubstituted spirocyclopropane derivatives in good yields and with a trans/cis ratio of up to >20:1 under mild conditions. An efficient base-promoted spirocyclopropanation of 2,3-dioxopyrrolidine derivatives with sulfoniumsalts is described. This reaction enables a novel concise access to
Practical and regioselective halo-trifluoromethylthiolation of sulfur ylides
作者:Hongmei Qin、Yimin Jia、Na Wang、Zhong-Xing Jiang、Zhigang Yang
DOI:10.1039/d0cc03171b
日期:——
practical and highly regioselective chloro- and bromo-trifluoromethylthiolation of sulfur ylides is reported using a difunctionalization strategy. In the reaction sequence, sulfur ylides presumably react with an electrophilic trifluoromethylthiolating reagent to generate an α-SCF3 substituted sulfonium salt intermediate, which then undergoes a substitution with nucleophilic halogens.
Chlorotrifluoromethylthiolation of Sulfur Ylides for the Formation of Tetrasubstituted Trifluoromethylthiolated Alkenes
作者:Na Wang、Yimin Jia、Hongmei Qin、Zhong-xing Jiang、Zhigang Yang
DOI:10.1021/acs.orglett.0c02747
日期:2020.9.18
ylides utilizing nucleophilic halide reagent and electrophilic SCF3 reagent. This cascade reaction is mild, highly practical, easy to manipulate, uses catalyst-free conditions, and demonstrates a wide substrate range with excellent functional group tolerance, furnishing E-selective products in good to high yields. The synthetic utility of this approach is documented through gram-scale preparation and