Chemoselective α,β-Dehydrogenation of Saturated Amides.

We report a method for the selective a,b-dehydrogenation of amides in the presence of other carbonyl moieties under mild conditions. Our strategy relies on electrophilic activation coupled to in situ selective selenium-mediated dehydrogenation. The a,b-unsaturated products are obtained in moderate to excellent yields and their synthetic versatility is demonstrated by a range of transformations. Mechanistic experiments suggest formation of an electrophilic Se(IV) species.