2-Bromo-3,3-difluoroallylic acetates were readily prepared by the reaction of carbonyl compounds with 1-bromo-2,2-difluorovinyllithium, generated from 1,1-dibromo-2,2-difluoroethylene, followed by acetylation. On treatment with butyllithium, the bromoacetates underwent selective 1,2-elimination of lithium acetate to afford mono- and disubstituted 1,1-difluoroallenes in high yields.
1,1-dibromo-2,2-difluoroethylene and n-butyllithium, with aldehydes or ketones, and subsequent acetylation, gives 2-bromo-3,3-difluoroallylic acetates. Elimination of these acetates with n-butyllithium affords 1,1-difluoroallenes in high yield. 3,3-Difluoro-2-iodoallylic acetates are similarly prepared from aldehydes or ketones on treatment with 2,2-difluoro-1-iodovinyllithium, generated from 1,1,
Transition metal-catalyzed nucleophilic addition of heteroatom nucleophiles to 1,1-difluoroallenes has been demonstrated here for the first time. Treatment of 1,1-difluoroallenes with O-nucleophiles, such as phenols, carboxylic acids, and sulfonic acids, facilitated unprecedented α-selective addition in the presence of AuCl3 or AuCl(PPh3)/AgSbF6 catalysts which afforded 1,1-difluoroallyl alcohol derivatives
Rhodium-Catalyzed Enantioselective N-Allylation of Sulfoximines
作者:Yang-yang Li、Bing Gao
DOI:10.1021/acs.orglett.3c00414
日期:2023.4.28
The N-functionalization of free sulfoximines is an important approach to modifying their chemical and biological properties for downstream applications. Here, we report a rhodium-catalyzed N-allylation of free sulfoximines (═NH) with allenes under mild conditions. The redox-neutral and base-free process enables chemo- and enantioselective γ-hydroamination of allenes and gem-difluoroallenes. Synthetic