Abstract: A ring expansion of a 6, 5 to 6, 6 system provides a stereo-controlled entry into the polyhydrochromanones. The steric and electronic requirements of such a process are probed. For the synthesis of verrucarol, such a process involves the synthesis of a norapotrichothecene followed by the rearrangement to the trichothecane skeleton-a process that may be reminiscent of the biogenesis of trichothecanes. The reaction of l-( ...
