Wd. Mcghee et al., CONVERSION OF AMINES TO CARBAMOYL CHLORIDES USING CARBON-DIOXIDE AS APHOSGENE REPLACEMENT, Tetrahedron letters, 35(6), 1994, pp. 839-842
Dialkyl carbamates, generated from amines and carbon dioxide, are conv
erted to their corresponding carbamoyl chlorides using thionyl chlorid
e in the presence of added tertiary amine base.