Trichloromethylphosphonates

In the presence of cuprous chloride, trichloromethylphosphonic dichloride (38) adds to a variety of alkenes and dienes via a free-radical process.40 There have been... 

Abstraction of positive halogen by trivalent phosphorus compounds represents an expeditious route for the synthesis of dialkyl l-(trimethylsilyl)methylphosphonates. Thus, treatment of diethyl trichloromethylphosphonate with hexamethylphosphorous triamide (HMPT) in the presence of McjSiCl in CgHg at room temperature affords diethyl l-(trimethylsilyl)-l,l-dichloromethylphos-phonate in 90% yield. Similarly, CCI4 and CICI3 have been reacted with trimethylsilylmethyl dialkyl phosphites. ... 

Other applications of dialkyl l-(trimethylsilyl)methylphosphonates include the reaction with dielec-trophihc reagents for the preparation of three-, four-, five-, and six-membered cycloalkylphospho-nates. Diethyl trichloromethylphosphonate is particularly well suited to this approach, and the exchange of the three halogen atoms with n-BuLi followed by sequential addition of Mc ,SiCl and (fl-dibromoalkanes results in the formation of a series of a-silylated cycloalkylphosphonates... 

Zanella, Y, Berte-Verrando, S., Diziere, R., and Savignac, P., New route to 1-formylalkylphosphonates using diethyl trichloromethylphosphonate as a precursor, J. Chem. Soc., Perkin Trans. 1, 2835, 1995. 

Jubault, P, Feasson, C., and CoUignon, N., Electrochemical activation of magnesium. A new, rapid and efficient method for the electrosynthesis of 1,1-dichloroalkylphosphonates from diisopropyl trichloromethylphosphonate. Tetrahedron Lett., 36, 7073, 1995. 

Grandin, C., Collignon, N., and Savignac, P, A practical synthesis of cycloalkylphosphonates from trichloromethylphosphonates. Synthesis, 239, 1995. 

The addition of diethyl 1-fluoro- or 1,1-difluoro-l-iodomethylphosphonates to nonactivated alkenes at room temperature in the presence of catalytic amounts of PdtPPh Jj affords good to excellent yields (63-91%) of mono- or difluorinated diethyl 3-iodo-l,l-difluoroalkylphospho-nates.285-287 yjjg CuCl-medialed addition of diethyl trichloromethylphosphonate to activated and non-activated alkenes has also been described. 2 8... 

Diethyl l-lithio-l-(trimethylsilyl)-l-chloromethylphosphonate is readily generated in THF at low temperature either from diethyl chloromethylphosphonate or diethyl trichloromethylphosphonate and n-BuLi (2 eq) in the presence of Me,SiCl (Scheme 3.66). 

A different approach involving the abstraction of a chlorine atom from diethyl trichloromethylphosphonate by means of PtNMejIs in CgHg at room temperature in the presence of McsSiCl gives diethyl l-(trimethylsilyl)-l,l-dichloromethylphosphonate in 90% yield.- °... 

Villemin, D., Sauvaget, E, and Hajek, M., Addition of diethyl trichloromethylphosphonate to olefins catalysed by copper complexes, Tetrahedron Lett., 35, 3537, 1994. 

Bakkas, S., Mouzdahir, A., Khamliche. L.. Julliard. M.. Peralez, E., and Chanon, M., Difference in behavior of the reactive electrophiles diethyl trichloromethylphosphonate and carbon tetrachloride towards triethyl phosphite. Phosphorus. Sulfur Silicon Relat. Elem., 157, 211, 2000. 

The addition of trilialomethylphosphonates to Michael acceptors has also been reported. Thus, in the presence of the cobaloxime(III)/Zn redox system, diethyl bromodifluoromethylphosphonate adds smoothly to acrylonitrile in EtOH to give the 1 1 Michael adduct in 67% yield. Similarly, the copper(I)-catalyzed addition of diethyl trichloromethylphosphonate to methacrylonitrile gives the Michael adduct in modest yield (31%). ... 

Detailed directions for preparation of trichloromethylphosphonic dichloride are to be found in Organic Syntheses.192... 

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