On the mechanism of base-induced rearrangements of epoxides to ketones: a formal synthesis of (S)-physoperuvine
作者:David M. Hodgson、Lesley A. Robinson、Matthew L. Jones
DOI:10.1016/s0040-4039(99)01810-9
日期:1999.12
The enantioselective α-deprotonation-rearrangement of trans- and cis-5-silyloxycycloheptene oxides (trans-8 and cis-8) using organolithiums in the presence of (−)-sparteine 16 or (−)-α-isosparteine 17 to give predominantly 4-silyloxycycloheptanone [(R)-9 (up to 87% ee), a known intermediate in the synthesis of (S)-physoperuvine (10), and (S)-9 (up to 71% ee), respectively] is described; the results
对映选择性的α-去质子化-重排反式-和顺-5- silyloxycycloheptene氧化物(反式- 8和顺式- 8),使用有机锂存在的情况下( - ) -鹰爪豆碱16或( - ) - α-isosparteine 17,得到主要4-甲硅烷氧基环庚酮[(R)-9(最高87%ee),是合成(S)-紫杉烷(10)和(S)-9(最高71%ee)的已知中间体),分别进行说明;结果表明了α环的打开机理。