Three‐Component Aza‐Diels‐Alder Reaction for the Syntheses of Tetrahydroisoquinoline Derivatives

Reported herein is the development of a normal electron‐demand, three‐component aza‐Diels‐Alder reaction between sultines, aldehydes, and amines. In the presence of Cu(OTf)2 as a Lewis acid catalyst, the use of sultines as o‐quinodimethane precursors in conjunction with the in situ generation of imines enables the facile preparation of various polysubstituted tetrahydro‐isoquinoline derivatives from readily available substrates. The synthetic utility of these products was further explored through a number of product transformations, including the syntheses of tricyclic N‐heterocycles.