(6) Recently an alternative preparation of C-phosphonoketenimines has been reported Kolodyazhnyi, 0. I.; Yakovlev, VN Zh. Obshch. Khim. 1980, 50, 55; Chem. Abstr. 1980, 92, 164046.(7) Diethyl (carbamoylallryl) phosphonates (1) are also prepared in the same yields by the Arbuzov reaction: Speziale, AJ; Freeman, RC J. Org. Chem. 1958, 23, 1883.