Construction of Tetrahydrospiro[carbazole‐1,2′‐indenes] and Dihydrospiro[carbazole‐1,3′‐indolines] via NH4I Promoted Three‐Component Reaction

Abstract

AbstractNH4I promoted three‐component reaction of indole, acetophenones and 2‐arylidene‐1,3‐indanediones in toluene at 120 °C afforded cis‐2,4‐diaryl‐substituted dihydrospiro[carbazole‐1,2′‐indene]‐1′,3′‐diones in good yields. Under same reaction conditions, NH4I promoted three‐component reaction of indole, acetophenones and (2‐oxoindolin‐3‐ylidene)malononitriles gave dihydrospiro[carbazole‐1,3′‐indolines] in moderate to good yields and with high diastereoselectivity. The reaction mechanism included sequential generation of 3‐alkenylindole, Diels‐Alder reaction and aromatization process.