Oxaphosphiranes: isolable phosphorus-containing epoxide rings.

Combining different heteroatoms in an epoxide-type ring having Lewis basic and acidic characteristics is challenging as it creates an increasing number of polar bonds and high ring strain energy. The first examples of isolable oxaphosphiranes, , epoxide rings with a phosphorus atom, have been synthesized using a facile and effective protocol starting from [pentacarbonyl{dichloro(trityl)phosphane}molybdenum(0)] (trityl = CPh), -butyllithium and commercially available fluorinated benzaldehydes. Reactions with various acids and bases will be described.

The quest for unligated oxaphosphiranes with phosphorus in different coordination numbers.

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--benzoquinone (TOB) reveal a significant destabilization upon increasing the coordination number at phosphorus from σ to σ, thus somehow supporting previous reports on such fleeting species. Theoretical studies provide insight into ring strain energy, ring/ring interconversion and the oxidation pathways.

Access and unprecedented reaction pathways of Li/Cl phosphinidenoid iron(0) complexes.

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.