Formal total synthesis of (±)-pseudomonic acids from dihydropyran
Abstract
A new, convenient, and stereoselective route to a central intermediate in pseudomonic acid synthesis via the cis-fused γ-lactone, 2,7-dioxabicyclo[4.3.0]non-4-en-8-one (3), is described. The required relative stereochemistry of the 2- and 5-side chains is established by a palladium(O)-mediated allylic substitution of the γ-lactone(3) by di-t-butyl sodiomalonate.