BifunctionalNHC-Catalyzed Asymmetric IntramolecularConjugate Addition via Noncovalent Interaction

Herein, we report a novel squaramide containing chiral bifunctional N-heterocyclic carbene (NHC) and its utilization in developing asymmetric intramolecular conjugate addition involving noncovalent interaction. Via concomitant activation of both electrophilic and nucleophilic centers of substrates, the reaction proceeds through a well-organized transition state, thereby affording products with up to 94% ee and a broad scope. The process is found to be scalable. The initial mechanistic study supports the bifunctional nature of the newly designed NHC.