Compounds of formula (II), (IIIa) or (IIIb)
(variables are described in the specification) are prepared by fluorination of β,γ-unsaturated alkyl silanes. These compounds are useful as building blocks in the pharmaceutical industry.
Coupling reactions of epoxide linked to a secondary oxygen group with Gilman reagents were examined. The regiochemical direction depended on whether there is TMS or MOM as a protective group of the secondary alcohol. anti-Epoxy alcohol 6 tended to react with Me2CuLi at the C4 position to generate 1,2-diol 22 as a major component. Epoxide 7 linked to a trimethylsilyloxy group displayed selective formation
Electrophilic alpha-thiocyanation of N-acyl carboximides using N-thiocyanatosuccinimide and hydrolytic cyclization of the adducts affords 5-substituted and 5,5-disubstituted 2,4-thiazolidinediones in good overall yields. alpha-Thiocyanation of chiral N-acyl carboximides proceeds with excellent diastereoselectivity, although partial racemization occurs during subsequent cyclization. (C) 2008 Elsevier Ltd. All rights reserved.
3-Silyl-3-Borylhex-4-Enoate: A Chiral Reagent for Asymmetric Crotylboration of Aldehydes
作者:Ruiqi Tong、Song Liu、Chen Zhao、Dongyang Jiang、Lu Gao、Wanshu Wang、Bengui Ye、Zhenlei Song
DOI:10.1021/acs.orglett.2c03195
日期:2022.10.28
A nonracemic 3-silyl-3-borylhex-4-enoate reagent has been developed. Its asymmetric crotylboration of aldehydes provides Z-anti-homoallylic alcohols possessing a trisubstituted vinylsilane in high yields with excellent stereo- and enantioselectivity. Diverse decoration of vinylsilane and ester groups, as well as formation of functionalized THF rings, showcase the potential of the approach in the synthesis