Photo-organocatalytic enantioselective α-hydroxylation of β-keto esters and β-keto amides with oxygen under phase transfer catalysis

An efficient and enantioselective photo-organocatalytic α-hydroxylation of β-dicarbonyl compounds using molecular oxygen was extended. This simple catalytic procedure is applicable to a range of β-keto esters and β-keto amides (30 examples) with a new series of C-2′-substituted phase transfer catalysts in good enantiopurity (up to 90% ee) and yield (up to 99%). Moreover, the reaction was successfully scaled up to gram quantity without any loss of enantioselectivity.