Diastereoselective synthesis of chiral amidophosphonates by 1,5-asymmetricinduction

We have investigated two simple diastereoselective syntheses of substituted beta -amidophosphonates. The first one involved a Michael addition to alph a,beta -unsaturated amides 6 and 8a-d, derived from chiral amino alcohols, and permitted the preparation of alkyl-substituted derivatives 7 and 9a-d w ith high diastereoselectivities (up to 95%) with the aid of a 1,5-asymmetri c induction, The second one, involving 1,5-inductive alkylation of chiral b eta -amidophosphonates 14a-c, was promising in terms of the yields, but the diastereoselectivities were disappointing (up to 50%). Finally, removal of the chiral auxiliary afforded phosphonocarboxylic acid, able to provide ac cess to a wide range of compounds of great interest for the synthesis of bi ologically active products.