Total Synthesis of Mevashuntin

The total synthesis of (+/-)-mevashuntin, a structurally unique naturally occurring pyrano-naphthoquinone-thiazolone, is described. The route is centered upon a late stage regioselective Diels-Alder reaction between two highly functionalized components, as well as an improved protocol for the one pot synthesis of benzothiazolones from ortho-bromoaryl isothiocyanates. The strategy results in a highly convergent route, providing access to the natural product in 11 steps from 3-(4-methoxyphenoxy)propanol and confirming its relative stereochemistry.