Catalytic Enantioselective Transfer Hydrogenation in Water

Significance

The authors developed a catalytic method for the enantioselective reduction of α-cyano and α-nitro ketones. The protocol is noteworthy for a number of significant merits: 1) easy preparation of iridium catalysts and their stability to moisture and air; 2) the use of water as a reaction media; 3) the use of formic acid as cheap, accessible, and operationally convenient reducing agent. The advantage of the methodology with ­regard to safety is apparent in comparison to the use of molecular hydrogen. As low as 0.25-0.5 mol% of the catalyst was sufficient to furnish the products with excellent yields and enantioselectivities.