ALTERNATIVE AND COMPLEMENTARY SYNTHETIC APPROACHES TO β CARBOXY-α-METHYLENE-γ-BUTYROLACTONE ETHYL ESTERS

Abstract

Alternative synthetic approaches to a variety of β substituted and carboxylated α-methylene-γ-butyrolactones have been developed. In the first approach the mandatory methylene unit was incorporated on precursor compounds at early stage of the synthesis on reliance with Horner-Emmons protocol. In the alternative approach which further tolerates multifarious substituents at γ-position of the lactone template the unsaturated moiety α to the lactone carbonyl group is connected at a later stage through a deprotonation / methoxymethylation / elimination sequence.

Keywords

• cyclization
• elimination
• enolate
• lactones
• transesterification
• Wadsworth-Emmons reaction