One‐Pot Synthesis of Aldehydes or Alcohols from CO2 via Formamides or Silyl Formates

The solvent-free N-formylation of 2-(methylamino)pyridine with CO2 and phenylsilane was catalyzed by Cu(OAc)2 alone to give N-methyl-N-(2-pyridyl)formamide called Comins-Meyers formamide. The X-ray crystallographic analysis of a copper complex revealed a paddle-wheel structure consisting of two copper ions bridged by four acetate ions with two molecules of 2-(methylamino)pyridine on both axial sites, which suggested (i) the improved solubility of the copper ion and (ii) the enhanced nucleophilicity of the acetate ion for the activation of phenylsilane. 1H NMR spectra of benzene-d6 solutions containing Cu(OAc)2, 2-(methylamino)pyridine, and phenylsilane showed a singlet signal at 2.62 ppm, which was assigned to a catalytically active Cu−H species, and this signal disappeared upon exposure to CO2. Comins-Meyers formamide synthesized from 2-(methylamino)pyridine via the copper-catalyzed hydrosilylation of CO2 under solvent-free conditions was directly subjected to the Grignard reactions in THF for the one-pot synthesis of aldehydes or alcohols. On the other hand, silyl formates prepared from CO2 and phenylsilane using tetrabutylammonium acetate (TBAA) as an organocatalyst were also found to be good precursors of alcohols. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.