Methylenomycin B: A New Synthesis from a β-Ketophosphonate

Abstract

Methylenomycin B (1) was prepared from diethyl 2-oxopropanephosphonate (5) in four steps in 26% yield. The key steps in this synthesis include the Wittig-Horner reaction of 5 with methylthioethanal (7) followed by the 1,4-addition of a propionyl anion equivalent to the α-enone 4 formed affording 4-(methylthiomethyl)-hepta-2,5-dione (3) which is an acyclic precursor of the title antibiotic.