Lateral lithiation of ethyl 4-acetyl-5-methyl-3-isoxazolyl carboxylate with 5,5-dimethyl-1,3-dioxanyl as a directing group

Abstract

Lateral lithiation of ethyl 4-acetyl-5-methyl-3-isoxazolyl carboxylate, a functionalized isoxazole AMPA analog, occurs cleanly at the C-5 methyl group with 5,5-dimethyl-1,3-dioxanyl as a directing group. The 4-acetyl isoxazole derivatives were transformed selectively by a modified Willgerodt-Kindler reaction into the corresponding homologated methyl esters after deprotection.