Asymmetric Catalytic Synthesis of Hexahydropyrrolo‐isoquinolines via Three‐Component 1,3‐Dipolar‐Cycloaddition

An asymmetric three‐component 1,3‐dipolar cycloaddition of 3,4‐dihydroisoquinolines, bromoacetates and α,β‐unsaturated pyrazole amide is realized by using a chiral N,N’‐dioxide‐Y(OTf)3 complex as the catalyst. The process includes a base‐promoted formation of dihydroisoquinolium ylides in situ, and a chiral Lewis acid‐catalyzed asymmetric [3+2] cycloaddition with α,β‐unsaturated pyrazole amides. A series of hexahydropyrrolo‐isoquinolines are obtained in moderate to good yields with excellent diastereo‐ and enantioselectivities. The asymmetric catalytic synthesis of hexahydropyrrolo‐isoquinolines by using a three‐component 1,3‐dipolar‐cycloaddition reaction is investigated.