Asymmetric Transfer Hydrogenation of gem-Difluorocyclopropenyl Ketones: The Synthesis and Functionalization of Enantioenriched cis gem-Difluorocyclopropyl Ketones.

The asymmetric transfer hydrogenation of gem-difluorocyclopropenyl ketones, catalyzed by a Noyori-Ikariya ruthenium complex, was developed to access substituted optically enriched cis-disubstituted gem-difluorocyclopropyl ketones, and the value of these latter building blocks was illustrated by the synthesis of heterocycles fused to the difluorocyclopropyl moiety.