An Umpolung Approach to Alkene Carboamination: Palladium Catalyzed 1,2-Amino-Acylation, -Carboxylation, -Arylation, -Vinylation, and -Alkynylation

Conventional approaches to Pd-catalyzed alkene 1,2-carboamination rely upon the combination of a <i>nucleophilic</i> nitrogen-based component and an internal C-based or external oxidant. In this study, we outline an umpolung approach, which is triggered by oxidative initiation at an <i>electrophilic</i> N-based component and employs “standard” organometallic nucleophiles to introduce the new carbon-based fragment. Specifically, oxidative addition of a Pd(0)-catalyst into the N–O bond of <i>O</i>-pentafluorobenzoyl oxime esters generates imino-Pd­(II) intermediates, which undergo 5-<i>exo</i> cyclization with sterically diverse alkenes. The resultant alkyl-Pd­(II) intermediates are intercepted by organometallic nucleophiles or alcohols, under carbonylative or noncarbonylative conditions, to provide 1,2-carboamination products. This approach provides, for the first time, a unified strategy for achieving alkene 1,2-amino-acylation, -carboxylation, -arylation, -vinylation, and -alkynylation. For carbonylative processes, orchestrated protodecarboxylation of the pentafluorobenzoate leaving group underpins reaction efficiency. This process is likely a key feature in related Narasaka–Heck cyclizations and accounts for the efficacy of <i>O</i>-pentafluorobenzoyl oxime esters in aza-Heck reactions of this type