Novel synthesis of rotenoid, pongarotene, by oxidative rearrangement using thallium(III) p-tosylate

Abstract

The synthesis of furano-rotenoid, pongarotene, by oxidative 1,2-aryl rearrangement of the sprirochromanone (11) using thallium(III) p-tosylate as key step has been described. Pongarotene (12) structure was confirmed by 2D NMR, HRMS and finally by X-ray crystallography. The sprirochromanones were synthesized by radical cyclization of chromone derivative (10). This methodology will be useful for the synthesis of naturally occurring rotenoids.