Cobalt‐Catalyzed Carbonylation of N‐Alkylbenzaldimines to ‘N‐Alkylphthalimidines’ (= 2,3‐Dihydro‐1H‐isoindol‐1‐ones) via Tandem C?H Activation and Cyclocarbonylation

The reaction of N‐alkylbenzaldimines with carbon monoxide (CO) in the presence of cobalt (Co) catalysts resulted in the formation of N‐alkylphthalimidines (Table 1). Their formation is proposed to occur by C? H activation of the aryl ring, migratory insertion of the hydride species into the benzaldimine functionality, CO coordination, and insertion into the Co? C bond, followed by reductive elimination of the N‐alkylphthalimidine and regeneration of the starting Co species (Scheme 4). Deuterium (²H)‐labeling NMR studies are consistent with this mechanism (Scheme 5).