Photoredox Organocatalysis: Asymmetric α-Perfluoroalkylation of Aldehydes

摘要

MacMillan and co-workers reportan efficient and highly enantioselective a-perfluo-roalkylation of aldehydes employing photoredoxorganocatalysis. The proposed mechanism in-volves an organocatalytic and a photoredox cata-lytic cycle. The organocatalyst I reacts with thealdehyde to form an enamine intermediate whichreacts with the trifluoromethyl radical, formed inthe photoredox catalytic cycle. The resulting a-amino radical is oxidized by an excited state spe-cies of the photocatalyst 2, generated by irradia-tion. The reduced photocatalyst is reoxidized bytrifluoromethyliodide to give 2 and a new trifluo-romethyl radical.