Cobalt‐Catalyzed Carbonylation of N‐Alkylbenzaldimines to ‘N‐Alkylphthalimidines’ (= 2,3‐Dihydro‐1H‐isoindol‐1‐ones) via Tandem CH 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 ( 2 H)‐labeling NMR studies are consistent with this mechanism ( Scheme 5 ).