Enantioselective Reduction of Imines Catalyzed by a Rhenium(V)−Oxo Complex

An air- and moisture-tolerant enantioselective hydrosilylation of N-phosphinyl imines employing a chiral Re(V)−oxo complex as a catalyst is described. The chiral catalyst is a cyanobis(oxazoline) (CNbox)-ligated rhenium−oxo complex of the general formula (CNbox)Re(O)Cl2(OPPh3). Using this catalyst, a wide range of aromatic imines (including cyclic, acyclic, and heteroaromatic), α-iminoesters, and α,β-unsaturated imines are reduced with good to excellent enantioselectivities.