title: Copper-catalyzed formal C - H carboxylation of aromatic compounds with carbon dioxide through arylaluminum intermediates.
abstract: The C - H bond carboxylation of various aromatic compounds with CO2 was achieved by the deprotonative alumination with a mixed alkyl amido lithium aluminate compound iBu3 Al(TMP)Li followed by the NHC-copper-catalyzed carboxylation of the resulting arylaluminum species, which afforded the corresponding carboxylation products in high yield and high selectivity. In addition to benzene derivatives, heteroarenes such as benzofuran, benzothiophene, and indole derivatives are also suitable substrates. Functional groups such as Cl, Br, I, vinyl, amide, and CN could survive the reaction conditions. Some key reaction intermediates such as the copper aryl and isobutyl complexes and their carboxylation products were isolated and structurally characterized by X-ray crystallographic analyses, thus offering important information on the reaction mechanism.
authors.affiliation: Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan), Fax: (+81) 48-462-4665.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ueno
authors.forename: Masanori
authors.initials: M
authors.lastname: Takimoto
authors.forename: Wylie W N
authors.initials: WW
authors.lastname: O
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nishiura
authors.forename: Takao
authors.initials: T
authors.lastname: Ikariya
authors.forename: Zhaomin
authors.initials: Z
authors.lastname: Hou
keywords: aromatic compounds; carbene ligands; carbon dioxide; carboxylation; copper