Light-Promoted Dearylation of Perfluorinated Aryl Sulfides with N -Heterocyclic Carbene-Borane.

The removal of the tetrafluoropyridinyl group tethered to a sulfur atom using a complex of N -heterocyclic carbene (NHC) with borane is described. The reaction is performed under blue light irradiation with a disulfide as radical initiator. The selective cleavage of S-Ar in preference to the weaker S-Alk bond is achieved as a result of aromatic radical substitution of the thiyl group by a NHC-stabilized boron-centered radical. Alkyl thiols, which are the primary products of the dearylation, are in situ oxidized or alkylated, affording disulfides or sulfides, respectively.