Enantioselective Synthesis of Dihydropyrazolo[3,4‐b]pyridin‐6‐ones via N‐Heterocyclic Carbene Catalyzed [3+3] Cycloaddition of α‐Bromoenals with 5‐Aminopyrazoles

Abstract

AbstractAn N‐heterocyclic carbene (NHC) catalyzed asymmetric [3+3] annulation of α‐bromoenals with 5‐aminopyrazoles is described. Using the established methodology, a structurally diverse set of high value dihydropyrazolo[3,4‐b]pyridine‐6‐ones were efficiently constructed in high yields (up to 99%) with excellent enantioselectivities (up to >99%). The easily available starting materials, broad substrate scope, mild reaction conditions, excellent yield and enantioselectivity make this strategy attractive for the asymmetric construction of pyrazolo‐fused pyridone derivatives.magnified image