Reductive dimerization and reduction of imines using lanthanum metal

Abstract

The treatment of N-benzylideneaniline (1a) with a half-equivalent of lanthanum metal and a catalytic amount of iodine gave the reductive dimerization product of 1a, a vic-diamine, in good yield. Various vic-diamines were synthesized from aldimines in this manner in moderate to good yields. Our findings suggest that electrons of a zero-valent lanthanum metal were efficiently utilized in this reductive dimerization. In the reaction of ketimines, however, a similar reductive dimerization did not take place, and the corresponding amines were formed as the sole products. © 2002 Wiley Periodicals, Inc. Heteroatom Chem.