On the Reaction of N-(Diphenylphosphinyl)-1-phenylethanimine with Aromatic Aldehydes Giving 4-Aryl-2,6-diphenylpyridine Derivatives

N-(Diphenylphosphinyl)-2-phenyl-1-azaallyl anion (1), generated from N-(diphenylphosphinyl)-1-phenylethanimine, reacted with aromatic aldehydes in a 2 : 1 molar ratio to give 4-aryl-2,6-diphenylpyridines in moderate yields. The intervention of N-phosphinyl-1-azadiene intermediates is proposed on the basis of the independent synthesis of an N-phosphinyl-1-azadiene and its conversion into a pyridine by the reaction with 1.