Asymmetric syntheses of (+)-negamycin, (+)-3-epi-negamycin and sperabillin C via lithium amide conjugate addition
作者:Stephen G. Davies、Osamu Ichihara、Paul M. Roberts、James E. Thomson
DOI:10.1016/j.tet.2010.10.067
日期:2011.1
and enantioselective reduction of ethyl 4-chloroacetoacetate and the diastereoselective conjugate addition of enantiopure lithium N-benzyl-N-(α-methylbenzyl)amide to an α,β-unsaturated ester have been used as the key steps in the total asymmetric syntheses of (+)-negamycin (in 13 steps and 24% overall yield), (+)-3-epi-negamycin (in 13 steps and 10% overall yield) and sperabillin C (in 17 steps and 13%
4-氯乙酰乙酸乙酯的化学和对映选择性还原以及对映纯N-苄基-N-(α-甲基苄基)酰胺对映体选择性共轭加成到α,β-不饱和酯中已被用作总不对称反应的关键步骤(+)的合成- negamycin(在13个步骤和24%的总收率),(+) - 3-外延-negamycin(在13个步骤和10%的总产率)和sperabillin C(在17个步骤,13%总收率)从可商购的原料中提取。