Synthesis and Absolute Configuration of Natural 2-Pyrones

2-Pyrones are frequently produced by microorganisms and often exhibit interesting bioactivities. Therefore, a short and easy synthetic access to these natural products is desirable. Synthetic routes to nectriapyrone, gibepyrone A, racemic gulypyrone A, (+)-germicidin C, (ent)-desoxygermicidin C and (ent)-prolipyrone A via a modular approach are presented, allowing the assignment of the absolute configurations of the latter three chiral compounds. The method failed for the synthesis of (ent)-phomapyrone B that was thus synthesized via a different route, resulting in an assignment of the absolute configuration of natural phomapyrone B.