The reactions of 2,6-di-tert-butyl-4-methoxyphenyl 2-methoxybenzoate 1a with several organolithium and -magnesium reagents are found to give the methoxy-substitution products 2 and/or the conjugateaddition products to the benzoate ring (3 and 4), preferring the latter products at the expense of the former with the increase of the electron-donating ability of the carbonion species. A SET mechanism