γ-Lactones from δ-lactones: total synthesis of the biosynthetic derailment product mupirocin H.

Two different strategies for the synthesis of functionalised γ-lactones from δ-lactones are described and used in a convergent synthesis of (+)-mupirocin H. The total synthesis is versatile and may be readily adapted for the preparation of further truncated metabolites from Pseudomonas fluorescens.