Enantioselective Reduction Catalyzed by (CN-Box)Re^V-Oxo Complexes

The authors have developed a series of chiral (CN-Box)ReV-oxo complexes which were employed in the catalytic hydrosilylation of ketones and imines. The protocol is advantageous in light of its mild conditions and functional group tolerance. High yields and enantioselectivities were obtained for hydrosilylation of aryl ketones, enones, aryl phosphinyl imines, allylic imines, and some α-imino esters. The notable feature of this chemistry is that reduction is carried out by means of high oxidation state complexes, which can be either pre-formed or used in situ. This feature was remarkably used in a one-pot Meyer-Schuster ­rearrangement-reduction protocol leading to ­allylic alcohols.