%0 Journal Article
%@ 0002-7863
%A Pan, X
%A Vallet, AL
%A Schweizer, S
%A Dahbi, K
%A Delpech, B
%A Blanchard, N
%A Graff, B
%A Geib, SJ
%A Curran, DP
%A Lalevée, J
%A Lacoîte, E
%D 2013
%F pittir:27586
%J Journal of the American Chemical Society
%N 28
%P 10484 - 10491
%T Mechanistic and preparative studies of radical chain homolytic substitution reactions of n-heterocyclic carbene boranes and disulfides
%U http://d-scholarship-dev.library.pitt.edu/27586/
%V 135
%X Reactions of 1,3-dimethylimidazol-2-ylidene-borane (diMe-Imd-BH 3) and related NHC-boranes with diaryl and diheteroaryl disulfides provide diverse NHC-boryl monosulfides (diMe-Imd-BH2SAr) and NHC-boryl disulfides (diMe-Imd-BH(SAr)2). Heating in the dark with 1 equiv of disulfide favors monosulfide formation, while irradiation with 2 equiv disulfide favors disulfide formation. With heteroaryl disulfides, the NHC-borane in the primary NHC-boryl sulfide product migrates from sulfur to nitrogen to give new products with a thioamide substructure. Most substitution reactions are thought to proceed through radical chains in which homolytic substitution of a disulfide by an NHC-boryl radical is a key step. However, with electrophilic disulfides under dark conditions, a competing ionic path may also be possible. © 2013 American Chemical Society.