title: Photoredox-Catalyzed Reductive Coupling of Aldehydes, Ketones, and Imines with Visible Light.
abstract: Ketyl radical and amino radical anions, valuable reactive intermediates for C-C bond-forming reactions, are accessible through a C=O/C=NR umpolung. However, their utilization in catalysis remains largely underdeveloped owing to the high reduction potential of carbonyl compounds and imines. In the context of photoredox catalysis, tertiary amines are commonly employed as sacrificial co-reducing agents. Herein, an additional role of the amine is proposed, in which it is essential for the organocatalytic substrate activation. The combination of photoredox catalysis and carbonyl/imine activation enables the reductive coupling of aldehydes, ketones, and imines under mild reaction conditions.
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen, Landoltweg 1, 52068 Aachen (Germany).
authors.forename: Masaki
authors.initials: M
authors.lastname: Nakajima
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen, Landoltweg 1, 52068 Aachen (Germany).
authors.forename: Eleonora
authors.initials: E
authors.lastname: Fava
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen, Landoltweg 1, 52068 Aachen (Germany).
authors.forename: Sebastian
authors.initials: S
authors.lastname: Loescher
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen, Landoltweg 1, 52068 Aachen (Germany).
authors.forename: Zhen
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Institute of Organic Chemistry, RWTH Aachen, Landoltweg 1, 52068 Aachen (Germany). Magnus.Rueping@rwth-aachen.de.
authors.forename: Magnus
authors.initials: M
authors.lastname: Rueping
keywords: diamines; photosensitizers; pinacol coupling; proton-coupled electron transfer; radical anions