Amide Bond Activation by Twisting and Nitrogen Pyramidalization

New Strategies for the Functionalization of Carbonyl Derivatives via α-Umpolung: From Enolates to Enolonium Ions

“…Notably, while similar reactivity had been previously observed independently by Hashmi, Ye, and Zhang, who generated labile N−O bonds through the addition of N-oxides to metal-activated alkynes, 20−22 precedent in the context of amide activation was significantly more restricted. 23 In fact, previous investigation was limited to a singular report by Ghosez, the pioneer of electrophilic amide activation, and co-workers. They described the formation of α,β-unsaturated amides through the treatment of α-branched amides with phosgene, followed by the addition of pyridine N-oxide, and notably, within this report, a sole example of α-chlorination was also shown.…”