Nucleophilic Addition versus SNAr Study: Chemo‐, Regio‐ and Stereoselective Hydrothiolation of Haloaryl Alkynes over S‐Arylation of Aryl Halides.

Base-mediated regio-, stereo-, and chemoselective nucleophilic addition of thiophenols onto bromo-substituted aryl alkynes over S-arylation of aryl halides is described. The regio- and stereochemistry of the products is well supported by spectral studies and X-ray crystallography. Competitive experiments showed that hydroamination is preferred over hydrothiolation. The stereoselectivity, competitive nucleophilic addition, and mechanistic pathway were corroborated by experimental and computational evidence.