Electrochemically promoted C-N bond formation from amines and CO2 in ionic liquid BMIm-BF4: Synthesis of carbamates.

A new electrochemical procedure for the synthesis of organic carbamates from amines and carbon dioxide has been developed using selective cathodic reduction of carbon dioxide in CO2-saturated room-temperature ionic liquid BMIm-BF4 solutions containing amines 1a-j, followed by addition of EtI as an alkylating agent. The synthesis was carried out under mild (PCO2 = 1.0 atm, t = 55 degrees C) and safe conditions, and the use of volatile and toxic solvents and catalysts (according to the growing demand for ecofriendly synthetic methodologies), as well as of any supporting electrolyte (for a very easy workup of the reaction mixture), was avoided. Carbamates 2a-j were isolated in good to high yields.