Iron‐Catalyzed Regioselective Double Hydrothiolation and Double Hydrophosphination Reactions Toward Acetylene C≡C Triple Bond

The development of atom‐economical methodologies for the regioselective incorporation of sulfur and phosphorus functionalities into simple alkynes remains a longstanding challenge. Herein, we report the iron‐catalyzed double hydrothiolation and double hydrophosphination of unsubstituted acetylene, providing access to either 1,1‐addition or 1,2‐addition products with high selectivity. The use of Cp*Fe(CO) 2 (Me) enabled the regioselective formation of methyldithioacetals from various thiols under solvent‐free conditions, and this is the first example of 1,1‐selective double hydrothiolation of acetylene. In contrast, the reaction with secondary phosphines afforded 1,2‐bis(diarylphosphino)ethanes as sole products. These findings not only expand the synthetic utility of acetylene as a feedstock chemical but also contribute to the development of chemistry that simultaneously creates two CE bonds (E is an atom having lone pair of electrons).