Rhodium(I)-Catalyzed Direct Carboxylation of Arenes with CO2 via Chelation-Assisted C-H Bond Activation
Hajime Mizuno, Jun Takaya, and Nobuharu Iwasawa*
Department of Chemistry, Tokyo Institute of Technology, O-Okayama, Meguro-ku, Tokyo 152-8551, Japan
dx.doi.org/10.1021/ja109097z |J. Am. Chem. Soc. 2011, 133, 1251–1253
ABSTRACT: Rh-catalyzed direct carboxylation of unactivated aryl C-H bond under atmospheric pressure of carbon dioxide was realized via chelation-assisted C-H activation for the first time. Variously substituted and functionalized 2-arylpyridines and 1-arylpyrazoles underwent the carboxylation in the presence of the rhodium catalyst and a stoichiometric methylating reagent, AlMe2(OMe), to give carboxylated products in good yields. The catalysis is proposed to consist of methylrhodium(I) species as the key intermediate, which undergoes C-H activation to afford rhodium(III), followed by reductive elimination of methane to give nucleophilic arylrhodium(I). This approach demonstrates promising application of C-H bond activation strategy in the field of carbon dioxide fixation.
