A versatile method for the synthesis of alpha,beta unsaturated lactones and the total asymmetric total synthesis of (-)-pironetin

The α,β unsaturated lactone moiety is a versatile synthetic intermediate in natural product synthesis and is also a structural feature present in many biologically important molecules. Herein we describe a convenient method for the preparation of such lactones in optically active form.; The natural product pironetin (PA-48153C) possess biological activity that is significant to both the agricultural and the pharmaceutical industry. We developed a laboratory synthesis of this largely unrecognized but important natural product. The synthesis successfully illustrates the general utility of several chemical transformations that have been developed in our laboratories. It also takes advantage of important transformations developed on similar endeavors by other laboratories. The synthesis culminates with the implementation of the aforementioned lactonization methodology.