Stereospecific Construction of Contiguous Quaternary All-Carbon Centers by Oxidative Ring Contraction

Oxidative ring contraction of cyclic a-formyl ketones was facilitated by the action of H2O2 under operationally simple and environmentally benign reaction conditions. The process was highly regioselective and enables stereospecific construction of contiguous quaternary all-carbon centers from stereodefined all-substituted all-cyclic ketones. The asymmetric syntheses of (+)-cuparene and (+)-tochuinyl acetate were also successively achieved by taking advantage of this novel protocol.

在操作简单且环境友好的反应条件下，过氧化氢的作用促进了环状α-甲酰基酮的氧化环收缩。该过程具有高度的区域选择性，能够从立体确定的全取代全环酮立体特异性地构建连续的季碳全碳中心。利用这一新方法还相继实现了（+）-花柏烯和（+）-对映贝壳杉烯酸乙酯的不对称合成。