Tandem gold-catalyzed dehydrative cyclization/diels-alder reactions: facile access to indolocarbazole alkaloids

Org Lett. 2015 Apr 3;17(7):1754-7. doi: 10.1021/acs.orglett.5b00528. Epub 2015 Mar 23.

Abstract

A gold-catalyzed synthesis of cyclic 2-oxodienes from readily prepared propargyl alcohols and the subsequent Diels-Alder reaction are reported. The dehydrative cyclization reactions proceeded smoothly, and the dienes formed in situ were demonstrated to undergo cycloaddition with a variety of dienophiles. This method offers a new strategy for the synthesis of indolocarbazole alkaloids, whereby the convergent synthetic design allows for differentiation between the indole nitrogens.