Synthesis of 2‐phosphinoxidomethyl‐ and 2‐phosphonomethyl glutaric acid derivatives

Michael addition of the corresponding anions derived from diphenylphosphine oxide, dialkylphosphites, and a cyclic phosphite to α‐methylene‐glutaric esters (1) afforded the title compounds (2–6). Double debenzylation of 2‐phosphono glutaric esters 4b and 5a by catalytic hydrogenation under the appropriate conditions gave the correspon‐ ding diacides 8 and 9, respectively.