Ruthenium–NHC‐Catalyzed Asymmetric Hydrogenation of Indolizines: Access to Indolizidine Alkaloids

Abstract

Crossing N-bridges! A ruthenium/N-heterocyclic carbene (NHC) complex serves as the catalyst for the high-yielding and completely regioselective and asymmetric hydrogenation of substituted indolizines and 1,2,3-triazolo-[1,5-a]pyridines. This method should provide ready access to bicyclic products bearing an N-bridgehead, a motif appearing in 25–30 % of all naturally occurring alkaloids.