Ruthenium-Catalyzed\nFormal Asymmetric Reductive Isomerization\nof α‑Hydroxyenones

The\nisomerization of α-hydroxyketones (acyloins) is a fundamental\ntransformation in carbohydrate chemistry. It has been found to play\nimportant roles in the metabolic processes of living organisms and\norganic synthesis. However, catalytic asymmetric acyloin isomerization\nremains a formidable challenge and has not been addressed. In this\nwork, we report the unprecedented ruthenium-catalyzed formal asymmetric\nreductive isomerization of α-hydroxyenones. The protocol affords\na variety of enantioenriched acyloins with a high level of enantioselectivities,\nand systematic mechanistic studies demonstrate a transformation involving\nthe isomerization of α-hydroxyenones and ruthenium-catalyzed\nasymmetric transfer hydrogenation. The work provides an alternative\napproach to realizing the challenging catalytic asymmetric acyloin\nisomerization.