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

Abstract

Dedicated to Professor Giambattista Consiglio on the occasion of his 65th birthdayThe 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 CÀH activation of the aryl ring, migratory insertion of the hydride species into the benzaldimine functionality, CO coordination, and insertion into the CoÀC 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).

Osmium Catalysts for Acceptorless and Base-Free Dehydrogenation of Alcohols and Amines: Unusual Coordination Modes of a BPI Anion

“…OsH6 34 [(η 6 -p-cymene)OsCl2]2 (10), 35 1,3-bis(6methylpyridyl-2-imino)isoindoline (HBPI) 36 were prepared according to the published methods. The formed imines were characterized by comparison of their 1 H NMR spectra with those previously reported: N-benzylidene aniline 14a , N-(phenylmethylene)methanamine 37 . The formed aldehydes were characterized by comparison of their 1 H NMR spectra with those previously reported: 4-methylbenzaldehyde 38 , 4chlorobenzaldehyde 38 .…”

Metal Complexes of Biologically Important Ligands, CLXXVI.[1] Formation of Peptides within the Coordination Sphere of Metal Ions and of Classical and Organometallic Complexes and Some Aspects of Prebiotic Chemistry

“…The reactions of N ‐alkylbenzaldimines with CO and with [CH 3 C(O)Co(CO) 3 P(o‐Tol 3 ] as catalyst do not give polypeptides instead N ‐alkylphthalimidines are formed, arising from C–H activation of the aromatic ring 136…”

Metal-Catalyzed Copolymerization of Imines and CO: A Non-Amino Acid Route to Polypeptides

“…[13] Evidence also indicates that cobalt is less prone to coordinate to an adjacent carbonyl group, which will be critically important for the present reaction. Although a phosphine-substituted acylcobalt complex has failed to catalyze this reaction, [8] we find now that the simple acylcobalt complex 1 without a phosphine ligand can effectively catalyze the copolymerization of imines and CO under suitable conditions, giving rise to the desired polypeptides as shown in Equation (1).…”

“…Of particular note is the copolymerization of imines and CO, which has long been suggested to be a potentially attractive route to polypeptides but is difficult to realize owing to lack of appropriate catalysts. [5][6][7][8] In 1998, Sen and co-workers [5] and Arndsten and coworkers [6] independently reported the first observation of imine insertion into acyl carbon-palladium bonds. This achievement constitutes a critical step toward metal-catalyzed copolymerization of imines and CO.…”