A route to 1,2-diols by enantioselective organocatalytic α-oxidation with molecular oxygen

A route to 1,2-diols by the direct organocatalytic enantioselective α-oxidation of aldehydes using molecular oxygen is presented. Protected commercially available chiral pyrrolidines catalyze the asymmetric α-oxidation of aldehydes with singlet molecular oxygen with high enantioselectivity to furnish the corresponding diols after in situ reduction in high yield with up to 98% ee. Electrophilic singlet molecular oxygen was photo or chemically generated (‘dark’ 1O2).