Alkylation of Potassium 1-(N-Benzyloxycarbonylamino)alkylphosphonates and Phosphinates in the Presence of 18-Crown-6

Abstract

During past several years we have been engaged in the synthesis of phosphono peptides, peptide analogues with phosphonic acid replacing C-terminal or N-terminal carboxylate moiety. These compounds are of interest not only because of their promise of direct practical applications^1,2 but also as a source of information about mechanisms of enzymatic reactions. ^1,3–5 Esters of N-blocked 1 -aminoalkylphosphonic and phosphinic acids are popularly used as starting substrates in multistep syntheses of phosphono peptides.^6–9 Although several methods for their preparation have been described ^6,10–13 the search for the new and useful methods of their synthesis is still in progress. In this paper we report that the use of complexes of potassium 1-(N- benzyloxycarbonylamiuo)alkylphosphonates and phosphates with 18-crown-6 as nucleophiles in the reaction with alkyl halides afforded the desired esters in good yields.