Organophosphorus chemistry. III. Synthesis of 3-Ethoxy-2-phenyl-1,3-azaphosphininane 3-oxide

Treatment of ethyl (3-bromopropyl)phosphonochloridate with benzylmagnesium chloride gave ethyl (benzyl)(3-bromopropyl)phosphinate. This underwent free-radical bromination to give ethyl (a-bromobenzyl)(3-bromopropyl)phosphinate Cyclization with aqueous ammonia gave 3-ethoxy- 2-phenyl-1,3-azaphosphininane 3-oxide. Attempts to prepare the 2-(pyridin-3'-yl)-substituted 1,3-azaphosphininane are also discussed.