Synthesis of the Mixed Alkyl Esters of Phenylphosphonic Acid by Two Variations of the Atherton–Todd Protocol

Abstract

ABSTRACTPhenylphosphonates with mixed alkyl groups were synthesized from ethyl phenyl‐H‐phosphinate by two modified Atherton–Todd methods. Using aqueous sodium hydroxide under phase transfer catalytic conditions, the alkyl ethyl phosphonates were obtained in only moderate yields. However, applying 1‐methylimidazole as the base, the diesters could be prepared in yields of 76–85%. The imidazole hydrochloride formed as a by‐product acts as an ionic liquid phase in the reaction, from which the base can be regenerated.