Chiral N-Heterocyclic Carbene Catalyzed Staudinger Reaction of Ketenes with Imines: Highly Enantioselective Synthesis of <i>N</i>-Boc β-Lactams
作者:Yan-Rong Zhang、Lin He、Xu Wu、Pan-Lin Shao、Song Ye
DOI:10.1021/ol702759b
日期:2008.1.1
N-heterocyclic carbenes (NHCs) were demonstrated to be efficient catalysts for the Staudinger reaction of ketenes with N-tosyl, N-benzyloxycarbonyl, or N-tert-butoxycarbonyl imines. Chiral NHC 8b, conveniently prepared from L-pyroglutamic acid, catalyzed the reactions of arylalkylketenes with a variety of N-tert-butoxycarbonyl arylimines to give the corresponding cis-beta-lactams in good yields with
N-杂环卡宾(NHCs)被证明是烯酮与N-甲苯磺酰基,N-苄氧基羰基或N-叔丁氧基羰基亚胺的Staudinger反应的有效催化剂。由L-焦谷氨酸方便地制备的手性NHC 8b催化了芳基烷基烯酮与各种N-叔丁氧羰基芳胺的反应,从而以良好的收率,良好的非对映选择性和出色的对映选择性(高达99%)提供了相应的顺式β-内酰胺。 ee)。讨论了通过向烯酮或亚胺中添加NHC引发的两种可能的催化途径。