Synthetic and computational investigation of neighboring group participation by a nucleophilic disulfide bond.

Disulfide bonds of 2-isocyanatophenyl methyl disulfide and 2- endo -isocyanato-6- endo -(methyldisulfanyl)bicyclo[2.2.1]heptane showed neighboring group participation in the formation of thiocarbamates. Natural Bond Orbital (NBO) analyses revealed that the unusual nucleophilicity requires a rigid through-space interaction between a lone pair of the disulfide bond and an antibonding orbital of isocyanate.