Reactivity of Ketenyl Anions towards Ammonia

Alkali metal ketenyls, [M(RCCO)], were found to exhibit diverging reactivities towards ammonia depending on the substitution pattern. Ketenyl anions with strong electron-withdrawing groups (R = CN or tosyl) react with NH3 to β-ketoamides, while the phosphinoyl substituteted systems (R = Ph2P(E), E = S, Se) activate all three N−H bonds, resulting in a trianionic triamide. This triamide exhibits a dimeric structure with the six potassium cations forming a unique planar triangular {K6}6+ cluster.