ChemInform Abstract: Hydrochalcogenation of Symmetrical and Unsymmetrical Buta‐1, 3‐diynes with Diaryl Dichalcogenides: Facile Entry to (Z)‐1‐(Organylchalcogeno)but‐1‐en‐3‐yne Derivatives. Issue 25 (5th June 2015)