Total synthesis of the mushroom metabolite (+)-calopin

A synthesis of (+)-calopin () was achieved employing a highly stereoselective ene reaction between 8-phenylmenthyl glyoxylate () and the β,β-dimethylstyrene . Transesterification of the resulting homoallylic alcohol , followed by allylic oxidation and hydrogenation yielded the δ-lactone which was deprotected to the natural product .