RESUMO
After more than 160 years of oxirane (epoxide) chemistry, the first derivative of a phosphorus analogue, namely oxaphosphirane, has been synthesized. Reactions with borane sulfane, a peroxy compound and elemental sulfur, as well as tetra-chloro-ortho-benzoquinone (TOB) reveal a significant destabilization upon increasing the coordination number at phosphorus from σ3 to σ4, thus somehow supporting previous reports on such fleeting species. Theoretical studies provide insight into ring strain energy, ring/ring interconversion and the oxidation pathways.
RESUMO
Complexes [Fe(CO)4(RPCl2)] (2) (a: R = CPh3, b: R = tBu) were used to generate the first examples of phosphinidenoid iron(0) complexes [Li(12-crown-4)(solv)n][Fe(CO)4(RPCl] (3a,b), characterized by NMR spectroscopy. The bonding situation of 3 was analyzed for a P-Me model complex using DFT calculations. Complex 3a (R = CPh3) reacted with H2O and MeOH to give selectively O-H bond insertion products 5 and 7; for the case of H2O, a multistep electrophilic reaction is supported by detailed DFT calculations. Clear-cut evidence for an unprecedented electrophilic reactivity of 3a was obtained as a reaction with MeLi led to P-chloro substitution. The intermediately formed phosphanido complex [Fe(CO)4(Ph3CPMe)] (8) was quenched with HCl or MeOTf to furnish neutral iron(0) complexes 9 and 10.
