Mechanistic and Preparative Studies of Radical Chain Homolytic Substitution Reactions of N-Heterocyclic Carbene Boranes and Disulfides
Citations Over TimeTop 10% of 2013 papers
Abstract
Reactions of 1,3-dimethylimidazol-2-ylidene-borane (diMe-Imd-BH3) 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.
Related Papers
- → A Practical and Controllable Enantioselective Synthesis of 2-Phenyl-1-cyclopropanecarboxylates via a Camphor-Derived Sulfonium Ylide(2005)28 cited
- → Application of α-Aminoalkyl Radicals as Reaction Activators(2021)14 cited
- → Controlling the fluoridophilicity of sulfonium boranes via chelation, Coulombic and hydrophobic effects(2019)5 cited
- → Substituent Effects of Positive Poles in Aromatic Substitution. II. The Nitration of Sulfonium and Selenonium Salts(1967)26 cited
- → Radical aromatic substitution with benzene chromiumtricarbonyl(2007)5 cited