α-Substituierte phosphonate—38: 1-dimethylamino-1-cyano-methanphosphonsäurediethylester, ein neues edukt zur darstellung von carbonsäuren, 1-cyanoenaminen und homoenolaten

Abstract

Alkylation of 1-dimethylamino-1-cyanomethanephosphonic acid diethyl ester ( 8), easily obtainable from diethyl phosphite and the 0,N-acetal 9, yields 1-alkyl derivatives 14. Elimination of HCN converts 14 into 1-phosphonoenamines 6. Carbonyl compounds react with 8 to give 1-cyanoenamines 15 which may be hydrolyzed to from the homologous carboxylic acid. Alternatively, deprotonation of 15 yields the homoenolate anions 17 which can be alkylated or hydroxyalkylated, permitting chain extension of carbonyl compounds through introduction of an α-carboxyl and a β-alkyl group. Acid catalyzed hydrolysis of 8 results in cleavage of the PC bond, leading to the corresponding α-dimethylamino alkanoic acids. A phosphonic acid 11 can be obtained from 8 by application of the silylester method. An unambigous assignment of E/ Z-isomers of the cyanoenamines 15 has been derived from 13C-NMR spectroscopy.