Total synthesis of spiroketal containing natural products: kinetic vs. thermodynamic approaches

Abstract

This review details part of a lecture delivered at the 20th ICHC in Palermo Italy, July 31-August 5 2005. The published total syntheses of reveromycin A (1) and the assigned structure for spirofungin B (26) are described. The approach to 1 utilized a hetero-Diels-Alder reaction to construct the spiroketal fragment in a kinetic stereocontrolled manner. The synthesis of the proposed spirofungin B (26) spiroketal fragment utilized a thermodynamically controlled cyclization of a protected dihydroxyketone precursor. This allowed for the reassignment of the structure of spirofungin B as epi-spirofungin A (48). ©ARKAT.