OXIDATION OF SUBSTITUTED 2-METHYL BENZOIC ACIDS AND ACRYLIC ACIDS BY S2O8(2-)-Ag(I); THEIR CONVERSION TO PHTHALIDES AND BUTENOLIDES THROUGH REARRANGEMENT OF ACYLOXYL RADICALS.
Ag (I) mediated persulphate oxidation of various 2-methyl benzoic acids and acrylic acids, co-catalysed by Cu (II), leads to unsaturated γ-lactones, together with decarboxylation products.Lactonisation proceeds through 1,5 hydrogen trasfer from intermediate acyloxyl radicals.