A New Class of Structurally Rigid Tricyclic Chiral Secondary Amine Organocatalyst: Highly Enantioselective Organocatalytic Michael Addition of Aldehydes to Vinyl Sulfones

A new class of chiral secondary amine organocatalyst was rationally designed as an efficient catalyst to catalyze the elusive Michael addition of aldehydes to vinyl sulfones. High yield and excellent enantioselectivities could be obtained at room temperature without having to resort to high catalyst loading, anhydrous solvents, and low temperatures. Efficient control of enamine conformation and face shielding as well as the rigid nature of the tricyclic skeleton, with an inherent chiral pocket, provide a well-organized chiral environment to effect this elusive reaction efficiently.

本研究合理设计了一类新型手性二级胺有机催化剂（chiral secondary amine organocatalyst），将其作为高效催化剂，用于催化颇具难度的醛与乙烯基砜（vinyl sulfones）的迈克尔加成反应（Michael addition）。在室温条件下即可获得较高产率与优异的对映选择性（enantioselectivities），无需采用高催化剂负载量、无水溶剂以及低温反应条件。该催化剂通过对烯胺构象（enamine conformation）与面屏蔽（face shielding）的高效调控，结合其固有的手性口袋（chiral pocket）与三环骨架（tricyclic skeleton）的刚性结构，构建了规整有序的手性环境，从而高效实现这一颇具难度的反应。