ε6-Phosphinine-and ε6-1,3-Diphosphinine Iron Complexes

Abstract Efficient synthetic routes are described, leading to novel η6-phosphinine- (1) and η6-1,3-diphosphinine (4, 5) iron(0) complexes. 1 is a catalyst for pyridine formation by a [2+2+2]-cyclic addition reaction of nitriles and alkynes and s4 is a useful source of unsaturated free four and six membered organophosphorus rings.