Copper-dipyridylphosphine-catalyzed hydrosilylation: enantioselective synthesis of aryl- and heteroaryl cycloalkyl alcohols.

The non-precious metal copper-catalyzed enantioselective hydrosilylation of a vast array of aryl cycloalkyl ketones with different ring sizes was studied systematically for the first time (up to 99% enantiomeric excess). The results demonstrated that the steric size of cycloalkyl groups has a significant influence on the reaction outcomes. The first stereoselective formation of a selection of cyclohexyl heteroaryl alcohols of up to 97% enantiopurity was realized as well. Dramatic temperature effects on both the enantiopurity and the absolute configuration of the alcohol products were observed in the reduction of some cyclohexyl pyridyl ketones.