Selective Carbonylation Routes to Thiocarbamates. An Alternative to Phosgene

A new route for the synthesis of thiocarbamates using a transition metal complex and CO as a replacement for phosgene has been discovered. The complex (PPh 3 ) 2 PdCl 2 reacts with N -benzylmethylamine, 4-chlorobenzenethiol, and CO to selectively generate a thiocarbamate. Kinetic studies and the isolation of several intermediates in this reaction allow for the proposal of a mechanistic scheme.