C-N and N-H Bond Metathesis Reactions Mediated by Carbon Dioxide

Article abstract of DOI:10.1002/cssc.201500318

Herein, we report CO₂-mediated metathesis reactions between amines and DMF to synthesize formamides. More than 20 amines, including primary, secondary, aromatic, and heterocyclic amines, diamines, and amino acids, are converted to the corresponding formamides with good-to-excellent conversions and selectivities under mild conditions. This strategy employs CO₂ as a mediator to activate the amine under metal-free conditions. The experimental data and in situ NMR and attenuated total reflectance IR spectroscopy measurements support the formation of the N-carbamic acid as an intermediate through the weak acid-base interaction between CO₂ and the amine. The metathesis reaction is driven by the formation of a stable carbamate, and a reaction mechanism is proposed.