A Three‐Component Reaction for the Efficient Construction of the 2′,11b′‐Dihydrospiro[indoline‐3,1′‐pyrido[2,1‐a]isoquinoline] Skeleton

Abstract

The three‐component reactions of isoquinoline, acetylenedicarboxylates, and 3‐phenacylideneoxindoles in ethanol at room temperature resulted in a mixture of two diastereoisomers of 2′,11b′‐dihydrospiro[indoline‐3,1′‐pyrido[2,1‐a]isoquinoline] derivatives, which were successfully separated and characterized. The regioselectivity and diastereoselectivity of this reaction were briefly discussed.

Sequential and direct multicomponent reaction (MCR)-based dearomatization strategies

“…In this direction, Yan and co-workers have described a three-component reaction of an isoquinoline, an acetylenedicarboxylate and 3-phenacylideneoxindole towards the generation of a diastereoisomeric mixture of 2′,11b′-dihydrospiro [indoline-3,1′-pyrido[2,1a]isoquinoline] derivative in ethanol at room temperature. 81 The three-component reaction of isoquinoline gave the two diastereoisomers in nearly equal yields. Mechanistically, the generated 1,4-dipole could react with 3-phenacylideneoxindole (91) directly to give the products 103 and 104 preferable in a concerted 1,4-cycloaddition pathway (Scheme 21A).…”