membered organic ring, are limited but known to be synthesizable from alkynes with bulky
electron‐donating groups. Metalla‐chalcogenirenium compounds have been synthesized
as stable compounds through the reactions of a cyclic metal‐carbyne complex—
metallapentalyne with PhSCl, PhSeCl or PhTeCl. As a result of the high strain in the three‐
membered metallacycles, the metalla‐chalcogenirenium cations react readily with the base …