Studies on peroxycompounds—XXVI: “SN2”-type decarbethoxylation of o-benzoyltartronates and benzoyloxycyanoacetates. New synthons for 2-hydroxycarboxylic esters and aldehydes

Diethyl O-benzoyl-R-tartronates 1; RH, C₂H₅, Ph undergo S_N2-type dealkylation and subsequent CO₂ elimination at 175–190°C in anhydrous or wet DMSO, with or without inorganic salts as catalysts giving the corresponding 2-benzoyloxyesters 2. Ethyl 2-benzoyloxy-2-benzylcyanoacetate 4 also undergoes decarbethoxylation (140°C, DMSO or wet DMSO) giving 6 in small yields (1–6%). The best yields of 6 (82%) were found when pyridine was the solvent and LiI the catalyst.