甲硅烷基化的氟代烯烃是具有互补反应性的重要合成中间体,在天然产物,药物和人造材料的构造中起关键作用。通过选择性脱氟甲硅烷基化将通常高度稳定的氟代烯烃转化为甲硅烷基化的氟代烯烃是一项艰巨的任务。本文中,我们报道了在烷氧基碱的存在下,各种氟代烯烃与甲硅烷基硼酸酯的简单,廉价和稳健的脱氟甲硅烷基化反应,以直接合成各种甲硅烷基化的氟代烯烃。该协议具有温和而安全的反应条件,可避免催化剂,过渡金属,配体和高反应温度,并能耐受各种氟代烯烃底物,而不会影响效率。N 2'或S N V取代,这是该碱基介导的脱氟甲硅烷基化的原因。
Palladium-Catalyzed Trimethylenemethane Cycloaddition of Olefins Activated by the σ-Electron-Withdrawing Trifluoromethyl Group
作者:Barry M. Trost、Laurent Debien
DOI:10.1021/jacs.5b07573
日期:2015.9.16
α-Trifluoromethyl-styrenes, trifluoromethyl-enynes, and dienes undergo palladium-catalyzed trimethylenemethane cycloadditions under mild reaction conditions. The trifluoromethyl group serves as a unique σ-electron-withdrawing group for the activation of the olefin toward the cycloaddition. This method allows for the formation of exomethylene cyclopentanes bearing a quaternary center substituted by
The electrochemical synthesis of fluorinated allyl silanes and boronates is disclosed. Through the electrogeneration of boryl and silyl radical a panel of α-trifluoromethyl or α-difluoromethylstyrenes was converted into the corresponding allyl silanes and boronates in good to excellent yields (64 examples, from 31 % to 95 % yield). A scale up of the reactions under continuous flow was showcased and