Obtention de tetrahydrofurannes fonctionnalises lors de l'action de reactifs organometalliques sur des γ,δ-epoxycetones
作者:Maurice Chastrette、Georges P. Axiotis
DOI:10.1016/s0022-328x(00)83466-x
日期:1981.2
The reaction of organolithium and organomagnesium reagents with γ,δ-epoxy ketones affords functionalized tetrahydrofurans by intramolecular cyclisation of an intermediate addition alkoxide. This cyclization is regioselective: the formation of a tetrahydrofuran is always observed while the tetrahydropyran isomer is never obtained. The oxiran ring opening is stereospecific and occurs with inversion of
有机锂和有机镁试剂与γ,δ-环氧酮的反应通过中间加成醇盐的分子内环化作用提供官能化的四氢呋喃。该环化是区域选择性的:总是观察到四氢呋喃的形成,而从未获得四氢吡喃异构体。oxiran开环是立体定向的,并且随着构型的反转而发生。然而,将有机金属试剂加到羰基官能团上具有低的立体选择性,并且环化作用以大约比例提供了四氢呋喃环的两个顺式和反式异构体。