Microwave-Enhanced Synthesis of Phosphonoacetamides

An efficient microwave protocol is described for the Michaelis–Arbuzov synthesis of secondary and tertiary N-aryl (and alkyl) (diethylphosphono)acetamides 1, by reaction of chloro- and bromoacetamides with triethyl phosphite in the presence of catalytic amounts of sodium iodide. Remarkable acceleration of the reaction (minutes vs. several hours) over conventional heating was achieved, together with improved product yields and purity, when bromoacetamides were employed as the substrates. Chloroacetamides were comparatively less reactive, leading to satisfactory yields only when a high excess of the reagent was employed.