Hypervalent-iodine induced quasi-Favorskii C-ring contraction of 12-oxosteroids: A shortcut to C-norsteroids

Abstract Treatment of 12-oxosteroids with PhI(OAc) 2 and KOH in refluxing methanol triggers a quasi-Favorskii C-ring contraction leading to the corresponding 11α-alcoxycarbonyl-C-norsteroids in moderate yields. This constitutes the first one-step synthetic alternative to C-norsteroids starting from 12-oxosteroids.