Synthesis of (±)-Nephromopsinic, (−)-Phaseolinic, and (−)-Dihydropertusaric Acids

Abstract

The formal syntheses of (±)-nephromopsinic acid, (−)-phaseolinic acid, and the first total synthesis of (−)-dihydropertusaric acid from (±)- and (−)-7-oxabicyclo[2.2.1]hept-5-en-2-one are described. These syntheses take advantage of a previously reported radical rearrangement (1,2-acyl migration). A remarkable iodide-mediated cleavage of a bicyclic system, followed by the introduction of the γ-chains via a mixed Kolbe electrolysis, are the key steps of these syntheses. This approach is general and could be applied for the preparation of all kinds of paraconic acids with excellent control of the stereochemistry.