A stable analogue of indole-2,3-quinodimethane: synthesis and Diels–Alder reaction of 2-methoxycarbonyl-4-[(p-methoxyphenyl)sulphonyl]-2,4-dihydropyrrolo[3,4-b]indole
Abstract
The 2,4-dihydropyrrolo[3,4-b]indole ring system, readily prepared from 1-[(p-methoxyphenyl)sulphonyl]-2-methyl-3,-formylindole, underwent Diels–Alder reaction with highly reactive dienophiles, e.g., benzyne and N-phenylmethoxy, to give cycloadducts in excellent yields.