Formation of Ketenimines via the Palladium-Catalyzed Decarboxylative π-Allylic Rearrangement of N-Alloc Ynamides

A new approach for the formation of ketenimines via a decarboxylative allylic rearrangement pathway that does not require strong stabilizing or protecting groups has been developed. The products can be readily hydrolyzed into their corresponding secondary amides or reacted with sulfur ylides to perform an additional [2,3]-Wittig process. Mechanistic studies suggest an outer-sphere process in which reductive alkylation is rate-limiting.