Copper-catalyzed stereo- and chemoselective synthesis of enaminones via Michael type addition

Abstract

An efficient strategy for the synthesis of $$\upalpha $$ , $$\upbeta $$ -unsaturated enaminones by the nucleophilic addition of N-heterocycles such as indole and imidazoles onto electronically bias alkynones under mild reaction conditions is described. Key feature of this reaction is the chemoselective addition of N-heterocycles onto ynones without affecting the $$1^{\mathrm{o}}$$ amino groups (aromatic and aliphatic) of 5-aminoindole and tryptamine. The stereochemistry of the products was controlled by the tuning of reaction time. The mechanism of the reaction involves the Michael type addition of N-heterocycles on ynones via allene formation.