Photoreductive Coupling of Aldimines. Synthesis of C2 Symmetrical Diamines

The photoreductive coupling of pyridine-, arene- and alkynecarboxaldimines is a very convenient procedure for the preparation of vicinal diamines in good to excellent yields. The usual trend gave an excess of meso diamine, which enhances the usefulness of this method. The procedure tolerates bulky groups such as tert-butyl and diphenylmethyl on the nitrogen atom.