2‐Phospha‐ and 2‐Arsaethynolates – Versatile Building Blocks in Modern Synthetic Chemistry

2‐Phosphaethynolates, particularly the sodium salts, Na(OCP), are exceedingly versatile nucleophiles, which renders these species important as precursors to phosphorus‐containing π‐conjugated heterocycles. Moreover, the 2‐phosphaethynolate anion serves as a potent phosphide transfer reagent giving rise to the first stable phosphinidine among other products. First studies also make evident that the phosphaethynolate ion serves as a fascinating ligand in coordination chemistry. Sodium salts of the long sought arsenic‐containing analogue, 2‐arsaethynolate, were synthesized only recently allowing the formation of arsenic‐based element organics and coordination compounds.