Temperature‐Dependent Regiodivergent [3 + 2] Cycloaddition of Azomethine Ylides With (E)‐5‐Benzylidenethioxoimidazolidin‐4‐One

Abstract

An efficient route is developed to gain access to novel dispiro[imidazolidine‐4,1′‐pyrrolo[2,1‐a] isoquinoline‐3′,3″‐indoline]‐2″,5‐dione skeletons by a one‐pot three‐component [3 + 2] cycloaddition reaction of (E)‐5‐benzylidenethioxoimidazolidin‐4‐ones, isatin derivatives, and 1,2,3,4‐tetrahydroisoquinoline. Interestingly we note that the reaction‘s regioselectivity depends on temperature, enabling the production of two regioisomericdispiro[imidazolidine‐4,1′‐pyrrolo[2,1‐a] isoquinoline‐3′,3″‐indoline]‐2″,5‐dione in high yield. In agreement with the experimental results, density functional theory calculations carried out at the 6‐31+g*(d,p)5 level of theory predicted that the [3 + 2] cycloaddition processes occur in an asynchronous concerted manner.