A Series of Two Oxidation Reactions of <i>ortho</i>-Alkenylbenzamide with Hypervalent Iodine(III): A Concise Entry into (3<i>R</i>,4<i>R</i>)‑4-Hydroxymellein and (3<i>R</i>,4<i>R</i>)‑4-Hydroxy-6-methoxymellein

A sequence of oxidation reactions of alkenamides with hypervalent iodine is described. Oxidation of ortho-alkenylbenzamide substrates selectively gave isochroman-1-imine products. The products underwent further oxidation in the presence of a Pd salt catalyst leading to regioselective C–H acetoxylation at the 8-position. A series of oxidations was applied to the crucial steps of asymmetric synthesis of 4-hydroxymellein derivatives.