Trimethylsilyl phosphites

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. ... 

Recently, good yields of glyphosate have been reported after hydrolysis using tris-trimethylsilyl phosphite in a similar sequence with 48 to generate the disilyl phosphonate triester intermediate 50 (S3). 

SnCl catalyses the formation of the (a-aryloxybenzyl) phosphonates (62) from diethyl trimethylsilyl phosphite and... 

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... 

Octanal (9.7 g, 75.4 mmol) at room temperature was added dropwise to a solution of diethyl trimethylsilyl phosphite (18.3 g, 87.1 mmol) in dry benzene (10 ml). After stirring for 3 h the solvent was removed, and distillation of the residual oil (104 to 105°C/0.04 torr) gave pure diethyl l-(trimethylsiloxy)octylphosphonate (23.1 g, 91%), which exhibited spectra and analytical data in accord with the proposed structure. 

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

Zon, J., Asymmetric addition of tris(trimethylsilyl) phosphite to chiral aldi-mines, Pol.. Chem., 55, 643, 1981. 

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. 

A convenient route to j3-phosphorus nitroxides involves the 1,3-addition of trimethylsilyl phosphites (e.g., diethyl) or trimethylsilyl phosphines (e.g., diphenyl) to aldo nitrones (e.g., a-PBN, DMPO), or keto nitrones (e.g., 2-Et-DMPO or 2-Ph-DMPO), to form a-phosphityl- or a-phosphinyl-O-silylhydroxyl-amines. Acidic hydrolysis provides the corresponding hydroxylamines which are easily oxidized to p-phosphorus-nitroxides (690). 

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... 

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). 

Trimethylsilyl phosphites can be anodically oxidized in the presence of arenes to form arylphosphonates (equation 30)35. 

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. 

Add tris(trimethylsilyl) phosphite 18 (3.9 mL, 3.5 g, 11.7 mmol) to a two-necked round-bottomed flask (25 mL) equipped with a magnetic stirrer bar and fitted with an argon inlet, efficient water condenser and a septum under an argon atmosphere. Cool the flask in an ice bath. 

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