title: Chelation-Assisted Nickel-Catalyzed Oxidative Annulation via Double C-H Activation/Alkyne Insertion Reaction.
abstract: A nickel/NHC system for regioselective oxidative annulation by double C-H bond activation and concomitant alkyne insertion is described. The catalytic reaction requires a bidentate directing group, such as an 8-aminoquinoline, embedded in the substrate. Various 5,6,7,8-tetrasubstituted-N-(quinolin-8-yl)-1-naphthamides can be prepared as well as phenanthrene and benzo[h]quinoline amide derivatives. Diarylalkynes, dialkylalkynes, and arylalkylalkynes can be used in the system. A Ni(0)/Ni(II) catalytic cycle is proposed as the main catalytic cycle. The alkyne plays a double role as a two-component coupling partner and as a hydrogen acceptor.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.
authors.forename: Luis C
authors.initials: LC
authors.lastname: Misal Castro
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Obata
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Aihara
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan. chatani@chem.eng.osaka-u.ac.jp.
authors.forename: Naoto
authors.initials: N
authors.lastname: Chatani
keywords: C−H activation; alkynes; aromatic homologation; chelate-assistance; nickel