STRUCTURE AND PROPERTIES OF PHOSPHONIUM YLIDES OBTAINED BY THE REACTION OF 3-PHOSPHORYLATED 1,4-DICHLORO-2-AZA-1,3-DIENES WITH SODIUM-AZIDE

The substituted vinylphosphonium salts of the general formula RCCl=C(N =CClAr)P(+)Ph(3) Cl- react with an excess of sodium azide in a peculia r manner. As a result, phosphonium ylides are produced. They are stabi lized with a nitrile and a 5-aryltetrazol-1-yl group or with two subst ituted tetrazolyl residues as confirmed by X-ray structural analysis. All the ylides obtained exhibit low reactivity and do not enter into t he Wittig reaction, but one of them was found to undergo the following sequence of transformations: N drop C-C=P- --> H2N-CO-C=P- --> -P=N-C O-CH2-.