Weakly Coordinating, Ketone‐Directed (η5‐Pentamethylcyclopentadienyl)cobalt(III)‐ and (η5‐Pentamethylcyclopentadienyl)rhodium(III)‐Catalyzed C−H Amidation of Arenes: A Route to Acridone Alkaloids. Issue 7 (9th January 2019)

• Record Type: Journal Article
• Authors: Bera, Sourav Sekhar; Sk, Md Raja; Maji, Modhu Sudan
• Is Part Of: Chemistry. Volume 25:Issue 7(2019)
• Page Start: 1806
• Page End: 1811
• Publication Date: 2019-01-09
• Subjects: amidation -- C−H activation -- cobalt -- heterocycles -- ketones; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201805376
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The weakly coordinating, ketone‐directed, regioselective monoamidation of aromatic ketones, chalcone, carbazole, and benzophenones was achieved by employing high‐valent cobalt and rhodium catalysis to access numerous biologically important molecular building blocks. This amidation proceeded smoothly with a variety of ketones and several amidating partners. The application of the products in the synthesis of various heterocycles, including acridones, indoles, quinoline, quinolones, quinolinones, and quinazolines, was also explored. The total synthesis of acridone‐based alkaloids, namely, toddaliopsin A, toddaliopsin D, and arborinine, and the formal synthesis of acronycine and noracronycin were also accomplished by applying this method. A mechanistic study revealed this amidation reaction follows a base‐assisted intermolecular electrophilic substitution pathway. Abstract : It rings true : The ketone‐directed, regioselective amidation of an assortment of arenes was achieved by employing high‐valent cobalt and rhodium catalysis. A variety of heterocycles were prepared by this protocol, and the total synthesis and formal synthesis of several alkaloids were explored. The process is thought to proceed through a base‐assisted intermolecular electrophilic substitution pathway.