Consecutive three-component synthesis of ynones by decarbonylative Sonogashira coupling

Abstract

Mild conditions! Decarbonylative carbonylation by consecutive glyoxylation of indoles, 7-aza-indoles, or pyrroles with oxalyl chloride and subsequent Pd/Cu-catalyzed decarbonylative alkynylation with terminal alkynes furnishes alkynones under very mild conditions. 4-(Indol-3-yl)-, 4-(7-aza-indol-3-yl)-, and 4-(pyrrol-2-yl)-2-amino pyrimidines can be readily obtained in a concise two-step synthesis starting from N-substituted indoles, 7-aza-indoles, or pyrroles (see scheme).