α-Substituierte Phosphonate. XXXI. Zur Reaktion von N,N,N′,N′-Tetramethylchlorformamidiniumchlorid mit P-III-Verbindungen

α-Substituted Phosphonates. XXXI. The Reaction of N,N,N′,N′-Tetramethyl Chloroformamidinium Chloride with P(III) Compounds N,N,N′,N′-Tetramethyl chloroformamidiniumchloride ( 4 ) does not react with triethyl phosphite (TEP) or isopropyl diphenylphosphinate to give the expected bisphosphoryl derivatives 7 and 11 , respectively, but primarily the monophosphorylated amidinium salts 6 and 10 respectively. The phosphine oxide 10 is stable, while 6 undergoes an elimination of ethyl chloride to the betain 8 . Even under more drastic conditions the reaction of 4 or 8 with TEP does not lead to the expected bis(dimethylamino)bisphosphonate 7 , but to the monoaminated bisphosphonate 1 , involving a reduction step. Similar reduction has been observed under mild conditions in Michaelis-Arbusov reaction of dichloromethylenimonium chloride, yielding the expected trisphosphonate 2 and the bisphosphonate 1 as a by-product.