Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States.
Org Lett. 2020 Dec 18;22(24):9683-9687. doi: 10.1021/acs.orglett.0c03737. Epub 2020 Dec 3.
The enantioselective Mannich reaction of 2-azirines with alkynyl ketones is achieved under Zn-ProPhenol catalysis, delivering various aziridines with vicinal tetrasubstituted stereocenters in high yields with excellent enantioselectivities. The bimetallic Zn-ProPhenol complexes activate both the nucleophile and the electrophile in the same chiral pocket. A unique intramolecular hydrogen bond is observed in the obtained Mannich adducts, which lowers the basicity of the product's aziridine nitrogen thus favoring enantioselective control and allowing catalyst turnover.
在手性锌-联苯酚催化剂的催化下，实现了 2-氮丙啶与炔基酮的对映选择性 Mannich 反应，以高产率和优异的对映选择性得到了各种带有相邻四取代立体中心的氮丙啶。双金属锌-联苯酚配合物在同一手性口袋中同时激活亲核试剂和亲电试剂。在得到的 Mannich 加合物中观察到独特的分子内氢键，降低了产物氮丙啶氮的碱性，从而有利于对映选择性控制，并允许催化剂转化。
