Asymmetric Tellurium‐Bonding Catalysis for Mannich Reaction

ABSTRACT

Chalcogen‐bonding catalysis has recently emerged as a powerful tool in organocatalysis. Nevertheless, its application in asymmetric transformations remains largely unexplored, primarily due to the scarcity of efficient chiral chalcogen‐bond donors. In this study, we report the design and synthesis of a series of chiral tellurium‐bonding catalysts based on an axially chiral 1,1′‐spirobiindane scaffold. Taking advantage of the highly directional and strongly polarizable tellurium‐centered donors along with a well‐defined C ₂ ‐symmetric chiral environment, these catalysts enable cooperative bifunctional activation of substrates. Under optimized conditions, the asymmetric Mannich reaction of isatin imines with dicyanoolefins proceeds smoothly to afford a broad range of products in good to excellent yields with high enantioselectivities. Mechanistic studies support a dual chalcogen‐bonding activation mode involving cooperative interactions between the two tellurium centers and the isatin imine substrate. This work constitutes a seminal contribution to asymmetric catalysis enabled by chalcogen bonding and offers a new platform for the development of chiral tellurium‐bonding catalysts and related enantioselective transformations.