Diels–Alder reactivity of pyrano[3,4-b]indol-3-ones, stable, synthetic equivalents of indole-2,3-quinodimethanes
Abstract
Pyrano[3,4-b]indol-3-ones (5), synthetic equivalents of indole-2,3-quinodimethanes, undergo Deils–Alder reaction with acetylenes and with benzyne to give carbazoles and benzo[b]carbozoles respectively.