Rhodium-catalyzed regio- and enantioselective allylic alkylation of pyrazol-5-ones with alkynes.

Abstract

A rhodium-catalyzed asymmetric allylic alkylation of pyrazol-5-ones with internal alkynes is illustrated. In the presence of a chiral rhodium-hydride catalyst, functionalized heterocyclic products bearing an all-carbon quaternary stereogenic center were obtained in high yields with satisfactory enantioselectivities. This protocol also features good regiocontrol and a high atom economy without stoichiometric by-product formation.