Hydroamination of Alkynes Catalyzed by a Cationic Rhodium(I) Complex

Abstract

The cationic Rh(I) dicarbonyl complex [{Rh((mim)2CH2)(CO)2}+BPh4-] (1), containing a bidentate bisimidazolylmethane ligand [mim = N-methylimidazol-2-yl], acts as an efficient catalyst for the intramolecular hydroamination of both terminal and nonterminal alkynes. The complex catalyzes the regioselective formation of nitrogen-containing heterocycles from aliphatic aminoalkynes and the cyclization of o-alkynylanilines to 2-substituted indoles in high yield.