Trimethylsilyl phosphites reactions

The ethoxycarbonyl group was developed for the protection of phosphonates. The derivative is prepared by reaction of tris(trimethylsilyl) phosphite with ethyl chloroformate and can be cleaved by hydrolysis of the ester followed by silyla-tion with bistrimethylsilylacetamide. ... 

Preparation of tris(trimethylsilyl) phosphite — Preparation of a silyl ester of a trivalent phosphorus acid for Michaelis-Arbuzov reaction... 

Several methods for the preparation of the parent compound in this system, tris(trimethylsilyl)phosphite, have been reported.114 118 The application of this and related reagents in reaction with alkyl halides has been reported and used for the preparation of a variety of phosphonic acid analogues of phospholipids.114119-124 Interestingly, alkyl chlorides appear to be more reactive with the silyl reagents than do alkyl iodides, a reversal of the normally observed trend with alkyl esters of the phosphorus acids. (The particular use of silyl phosphorus reagents for the synthesis of biologically significant compounds has... 

The preparation of optically active analogues of the natural amino acids has proven reasonable using the reaction of tris(trimethylsilyl) phosphite with chiral aldimines prepared from optically active amines.225 The asymmetric induction has been observed to be as high as 80%, a significant competitive process compared to the multistep approaches available.226227 An alternative one-step approach involving asymmetric induction upon addition to an aldimine derived from a chiral N-substituted urea provided a product with less desirable optical purity.228... 

Symmetrical cyclic triazines (masked imines) have been used in reaction with diethyl trimethylsilyl phosphite to provide phosphonates bearing silyl-substituted a-aminophosphonates.349... 

To 2,3-dioleoyloxy-l-iodopropane (3.65 g, 5 mmol) was added tris(tri-methylsilyl) phosphite (15.05 g, 50 mmol), along with a trace of butyl hydrogen phthalate. The reaction mixture was stirred under a static nitrogen atmosphere with heating at 125°C for 16 h. After this time, excess tris(trimethylsilyl) phosphite and iodotrimethylsilane were removed by high vacuum distillation (bath 100°C) to leave a colorless oil. The residue was dissolved in THF water (9 1, 50 ml) and allowed to stand in the dark at room temperature for 12 h. The solvent was... 

Hata, T., Sekine, M., and Kagawa, N., Reactions of tris(trimethylsilyl) phosphite with alkyl halides, Chem. Lett., 635, 1975. 

Hata, T., Hashizume, A., Nakajima, M., and Sekine, M., A convenient method of ketone synthesis utilizing the reaction of diethyl trimethylsilyl phosphite with carbonyl compounds, Tetrahedron Lett., 363, 1978. 

Attack on Oxygen. Nitrones have been deoxygenated to the parent imine with trimethyl phosphite under vigorous conditions.45 Virtually quantitative yields of the enol-phosphates (54) and (55) were obtained from the reaction of tris(trimethylsilyl) phosphite with a-diketones and /j-benzoquinone. 4 6... 

Triaryl phosphite-ozone adducts, 706 Tri( -butyl)silyl peroxides, bis(trimethylsilyl) peroxide reactions, 796 Trichloroacetyl chloride, from tetrachloroethene, 731... 

A variety of pyrrole ring closure reactions are conveniently formulated as proceeding via nitrene intermediates, although it is doubtful whether a free nitrene is involved. Pyrolysis of o-nitrobiphenyls with iron(II) oxalate (61T(16)80), or reduction under milder conditions with triethyl phosphite (65JCS4831) or tris(trimethylsilyl) phosphite (79TL375), leads to the carbazole, as does the pyrolysis or photolysis of 2-azidobiphenyls (Scheme 3) (75JA6193). 

This protocol was used by Iyer and co-workers in their synthesis of potential antiviral prodrugs,46 and is derived from the method of Sekine and Hata.50 It is important not to use excess tris(trimethylsilyl) phosphite (18) in such reactions to avoid formation of carbonyl adducts (20 Scheme 11). Removal of the trimethylsilyl groups is facile (e.g. methanolysis yields the free phosphonic acids) and may be undertaken on the crude product. 

If pentafluoropropanonc is used as the ketonic reagent, reaction with trimethylsilyl phosphites gives products analogous to 15 in yields of up to 98%. Silylaminophosphane 17 reacts with hexalluoroacctonc to provide the imide 18. 

Diethyl l-trimethylsilyloxyethylphosphonate, CH,CH-P(0)(0C2H5)2 ( ) The reagent is prepared by reaction of acetaldehyde and diethyl trimethylsilyl phosphite. 

The trimethylsilyl group is also labile in the products (10) and (11) of the reaction between dialkyl trimethylsilyl phosphites and azides R 2P(0)Ns. N.m.r. spectroscopy has been used to show that the formation of (11) is favoured when R is a... 

When a fluorine atom in ( .I is replaced by another halogen, a fluorine atom rather than a chlorine" or iodine atom is eliminated as alkyl fluoride from the reaction with trialkyl phosphites. Trimethylsilyl phosphites react with perfluoroalkenes to give fcrs(ti iiuclhylsilyl) perfluoroalke-nylphosphonates in very good yields (81-95%), - probably because of the greater nucleophilicity of the trimethylsilyl phosphites and the stability of fluorotrimethylsilane. ... 

Wessolowski, H., Rdschenthaler, G.-V., Winter, R., and Gard, G.L., 2,2-Dilhioro-l-(pcnlalhioro-Z -sulfanyl)]ethylene and l,L3,3,3-pentafluoropropene. Reactions with diethyl(trimethylsilyl) and frw(trimethylsilyl)phosphite. Phosphorus, Sulfur Silicon Relat. Elem., 60, 201, 1991. 

Sekine, M., Okimoto, K. and Hata, T., Silyl phosphites. Part 6. Reactions of trzh(trimethylsilyl) phosphite with a-halocarbonyl compounds,Am. Chem. Soc., 100, 1001. 1978. 

Both diethyl trimethylsilyl phosphite and tris(trimethylsilyl) phosphite participate in conjugate addition reactions with a,p-unsaturated nitriles.With acrylonitrile, addition occurs readily at 120°C at the P position, with transfer of the silyl ester linkage to the a position of the nitrile, to give 2-silylated 2-cyanoethylphosphonates in 46-72% yields. Protodesilylation with a proton donor leads to the simple 2-cyanoethylphosphonates (Scheme 6.28). ... 

Trimethyl phosphite does not react with chloroacetyl chloride through a Michaelis-Arbu-zov/Perkow reaction sequence. It gives an acylpseudophosphonium salt, which, in turn, reacts readily with trimethyl phosphite to give a new adduct. Subsequent warming affords dealkylation to give the final dimethyl l-(dimethoxyphosphinyloxy)vinylphosphonate (Scheme 7.3). More interesting from the mechanistic standpoint is the use of diethyl trimethylsilyl phosphite. In reaction with chloroacetyl chloride at 30°C, the initial adduct loses MejSiCl rapidly to give diethyl 2-chloroacetylphosphonate in 37% yield." ... 

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