Plausible pathway for IH catalyzed hydro- thiolation/selenation reaction
A plausible pathway has been proposed for the Imidazol-2-ylidene (IH) catalyzed hydro- thiolation/selenation reaction (Scheme 1) which makes use of the high Bronsted basicity of NHCs in initiating the reaction. NHC can abstract the thiolic or acetylenic proton, but our computations proved acetylenic activation by NHC to be a much more energy consuming process (by 16.81 kcal/mol at B3LYP/6-31+G(d) level). This indicated that the given proposed pathway proceeding through thiol activation would be more feasible.
Scheme 1 Envisioned pathway for NHC catalyzed acetylene hydrochalcogenation reaction