A Stereoselective Entry into Functionalized 1,2-Diamines by Zinc-Mediated Homologation of α-Aminoacids
作者:Cam Thuy Hoang、Valérie Alezra、Régis Guillot、Cyrille Kouklovsky
DOI:10.1021/ol0708020
日期:2007.6.1
stereoselective synthesis of 4,5-disubstituted imidazolidines-2-ones from alpha-aminoacids has been developed: the key steps are a Blaise reaction of bromoacetate on alpha-aminonitriles and further reduction. Although reduction with sodium cyanoborohydride afforded a mixture of cis and trans isomers 6a-e with moderate to good stereoselectivity, reduction with sodium in liquid ammonia gave the trans isomers
已经开发了由α-氨基酸进行的一般的立体选择性合成4,5-二取代的咪唑烷-2-酮的方法:关键步骤是溴乙酸在α-氨基腈上的布莱斯反应,并进一步还原。尽管用氰基硼氢化钠还原得到具有中等到良好的立体选择性的顺式和反式异构体6a-e的混合物,但是用液氨中的钠还原得到具有完全立体选择性的反式异构体8a-e。尿素的酸性水解得到4-氨基-吡咯烷酮,其可以是β,γ-二氨基酸或3-氨基吡咯烷的前体。