G's-selective preparation of 2,2-difluorocyclopropyl ketones via non-metal hydride reduction of 2,2-difluorocyclopropenyl ketones

摘要

Diastereoselective reduction of gem-difluorocyclopropenyl ketones was accomplished by their Bronsted acid catalyzed reactions with the non-metal based hydride transfer reagent, Hantzsch ester (diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate) (HEH). The high yield reactions produced a significantly ris-enriched product mixture, from which the ris-isomer could be readily separated by column chromatography.