PHOSPHORYLATION OF ENAMINEHYDRAZONES AS AN EFFICIENT ROUTE TO DIAZAPHOSPHOLINES AND DIAZAPHOSPHOLES

1,2,3-diazaphospholines of new type containing an enamine residue, con jugated with the diazaphospholine cycle, were synthesized by phosphory lation of N,N-dimethyl- and N-substituted hydrazones of omega-formyl-1 ,3,3-trimethyl-2-methyleneindol using phosphorus(III) halides. Reversi ble ionization of the P-Br bond was observed for a 2-N-methyl-3-P-brom odiazaphospholine in polar solvents. The ionization is caused by stabi lization of the phosphenium ion by electrondonating methyl and enamine group. Analogously, 2-N-phenyl-3-P-bromo- as well as 3-P-chloro-1,2,3 -diazaphospholines give stable phosphenium ions only after treatment o f sodium tetraphenylborate or trimethylsilyl trifluoromethanesulfonate .