OXIDATIONS OF TRIETHYL ALPHA-PHOSPHONOACRYLATE - EPOXIDATION TO TRIETHYL ALPHA-PHOSPHONOACRYLATE OXIDE BY HYPOCHLORITE AND FORMATION OF TRIETHYL DIHYDROXYPHOSPHONOACETATE WITH RUO(4)-PERIODATE

Oxidation of the methylidene double bond in triethyl alpha-phosphonoac rylate 2 by O3, catalytic RuO4 (RuO2/NaOCl, RuO2/NaIO4) and stoichiome tric RuO, was investigated as a route to alpha-oxygenated phosphonoace tate derivatives. Ozonation of 2 gave a mixture of products containing , in one experiment, triethyl phosphonoglyoxylate 1 as a minor (<5%) c omponent. Efforts to prepare ethylidene compounds analogous to 2 (as a lternative ozonation substrates) using known routes for synthesis of c orresponding diethyl oxomalonate derivatives were unsuccessful. Treatm ent of 2 in biphasic H2O/CCl4 with catalytic RuO4 using NaOCl as co-ox idant or with NaOCl alone produced a novel epoxide product, triethyl a -phosphonoacrylate oxide (7) in up to 79% isolated yield. When NaOCl w as replaced with NaIO4 as the RuO2 reoxidant (H2O/CHCl3), the major re action product in the aqueous phase was identified by C-13 and P-31 NM R as triethyl dihydroxyphosphonoacetate 8, the hydrate of the ketone 1 . Reaction of 2 with stoichiometric RuO4 in CCl4 did not provide 1. A convenient modification in the synthesis of 2 is also described, and i ts C-13 and P-31 NMR spectra are reported.