A procedure for the enantioselective synthesis of α-substituted glutamates and pyroglutamates via a cyclopropenimine-catalyzed Michael addition of amino ester imines is described. Enantioselectivities of up to 94% have been achieved, and a variety of functional groups were found to be compatible. The impact of the catalyst structure and imine substitution is discussed. Compared to other methods, this protocol allows for a broader and more enantioselective access to pyroglutamate derivatives.
通过环
丙烯亚胺催化的
氨基酯
亚胺的迈克尔加成,描述了一种合成α-取代谷
氨酸和
吡咯谷
氨酸的对映选择性程序。已经实现了高达94%的对映选择性,并发现多种官能团是兼容的。讨论了催化剂结构和
亚胺取代的影响。与其他方法相比,这种方案允许更广泛和更对映选择性地获得
吡咯谷
氨酸衍
生物。