Efficient and clean synthesis of N-alkyl carbamates by transcarboxylation and O-alkylation coupled reactions using a DBU–CO2 zwitterionic carbamic complex in aprotic polar media

N-Alkyl carbamates were obtained with good to excellent yields by clean and mild transcarboxylation of several amines with the previously synthesized DBU–CO2 complex and subsequent O-alkylation. Transcarboxylation was found to be selective, as only carbamate was formed from 1-hydroxy-2-aminobutanol.