Tandem Phenolic Oxidative Amidation-Intramolecular Diels-Alder Reaction: An Approach to the Himandrine Core

An oxidative cyclization of dienic sulfonamides mediated by iodobenzene diacetate in TFA, followed by a tandem intramolecular Die Is Alder reaction, achieves desymmetrization of a locally symmetrical dienone with good levels of diastereoselectivity and leads to valuable synthetic intermediates for the himandrine alkaloids.