Diethyl trichloromethylphosphonate

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. 

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%). ... 

Diethyl trichloromethylphosphonate (16) reacts with ribonucleotides, and presumably with other vicinal 1,2-diols, in the presence of triethyl-amine to give a mixture of the 2 - and 3 -phosphates. The readily available ct-hydroxyphosphonate esters (17) rearrange in base to the phosphate... 

Reactions of Phosphonic and Phosphinic Acids and their Derivatives.—Diethyl trichloromethylphosphonate is a useful reagent for the preparation of ethyl esters of carboxylic acids, even in those cases with considerable steric hindrance the yields are very high. ... 

Esterification.—iVAWW -Tetramethylchloroformamidinium chloride, which is readily prepared from iVAWW -tetramethylurea and oxalyl chloride, is an efficient reagent for the esterification of carboxylic acids with alcohols yields of between 66 and 97% are obtained, and the method has also been applied to macrolide synthesis. A modified one-pot procedure for the esterification of carboxylic acids, using phenyl dichlorophosphate-dimethylformamide complex, has appeared. A simple method of activation of carboxylic acids, using methanesulphonyl chloride and triethylamine followed by addition of the alcohol and 4-dimethylaminopyridine, leads to esters in 57— 96% yield for thirteen examples. 0-Methylcaprolactim reacts with carboxylic acids to give methyl esters in 73—91 % yield for seven examples and 2-iodoethyl esters are prepared from acyl chlorides, ethylene oxide, and sodium iodide. Transesterification, catalysed by titanium(iv) alkoxides, provides an effective method for synthesis of esters. Diethyl trichloromethylphosphonate reacts with carboxylic acids to give ethyl esters via transesterification, in 52 to 98 % yield. ... 

The enolate of t-butyl a-chloro-a-trimethylsilylacetate condenses with carbonyls to give a-chloro-a,)S-unsaturated esters in up to 50% yield. An alternative, one-pot route to this class of compound (Scheme 41) uses diethyl trichloromethylphosphonate as starting material yields are reported to be between 70 and 85%. °... 

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