Diethyl trimethylsilyl phosphite

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

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

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., 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. 

The related reagent diethyl trimethylsilyl phosphite, (C2H50)2P0Si(CH3>3 (5), has been used to prepare ketones from aldehydes (equation I). 

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

Moreover, the addition of diethyl trimethylsilyl phosphite to the A-trimethylsilylimine of (S )-O-triisopropylsilyllactic aldehyde turned out to be highly stereoselective. The major dia-stereomer was separated and transformed into enantiopure (15,25)-phosphothreonine68. 

An alternative procedure for the preparation of diethyl cyanobenzylphosphonates uses the addition of diethyl trimethylsilyl phosphite to P-nitrostyrenes in the presence of TiCl4. The silyl functionality is transferred to the oxygen to form nitronates, which, in the presence of low-valence titanium generated in situ, are converted to diethyl cyanobenzylphosphonates in 74-91% yields (Scheme 6.19). s ... 

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." ... 

Similarly, diethyl trimethylsilyl phosphite reacts with acetyl bromide at low temperature to produce diethyl 1-oxoethylphosphonate in 83% yield. Diethyl trimethylsilyl phosphite, on reaction with ketene, gives diethyl l-(trimethylsilyloxy)vinylphosphonate, which can be hydrolyzed or alcoholyzed to diethyl 1-oxoethylphosphonate. ... 

Diethyl acylphosphonates, on treatment with diethyl trimethylsilyl phosphite at room temperature, produce high yields of symmetric diethyl (l-trimethylsilyloxy)alkylidenediphosphonates (Scheme The same reaction has been applied to diphcnyl(trimethylsilyl)phosphine. "... 

By contrast, diethyl 2,2,2-irichloro-l-oxoethylphosphonate reacts with diethyl trimethylsilyl phosphite by abstraction of chlorine and phosphorylation of the generated enol form." ... 

Novikova, Z.S., Mashoshina, S.N.. Sapozhnikova, T.A., and Lutsenko. LE. Reactions of diethyl trimethylsilyl phosphite with carbonyl compounds, Zh. Obshch. Khim.. 41. 2622. 1971 J. Gen. Chem. USSR (Engl. Transl.), 41, 2655, 1971. 

A new and facile synthesis of diethyl (a-cyanobenzyl)-phosphonates starts from diethyl trimethylsilyl phosphite in reactions catalyzed by TlCl and displacements in... 

A full paper has appeared on the preparation of P-chiral fullerenephosphinites reported last year. A series of functionalised alkylphenylphosphinic acids has been synthesised by addition of in situ prepared bis(trimethylsilyl) phenylphos-phonite (12) to a range of electrophiles, e.g. (IS). Stereoselective syntheses of the four diastereomers of phosphothreonine have been described which are based on the stereoselective addition of diethyl trimethylsilyl phosphite (14) to protected lactaldehyde (15) or its imine. A similar procedure gave access to phosphomycin... 

Yet another synthesis which employs phosphorus(III)triesters is the reaction which occurs between diethyl trimethylsilyl phosphite and bis(alkylthio)ketals more specifically, such acetals of aromatic aldehydes react in the presence of a Lewis acid (SnCl4 was actually employed) to give diethyl (a-alkylthiobenzyl)phosphonates (reaction 17) ... 

A one-pot process has been devised for the synthesis of dialkyl [(a-phenylamino)ben-zyljphosphonates from dialkyl hydrogenphosphonate, benzaldehyde and aniline, presumably adaptable for other aromatic amines or aldehydes To avoid multiple reactions of the Mannich type when using a primary amine and a particularly reactive carbonyl component such as formaldehyde, initial silylation of the amine, or the use of diethyl trimethylsilyl phosphite, are valuable moderating variations The amine can be replaced by a carboxamide" or carbamate ester, conveniently the benzyl ester , and the product can then be selectively deacylated with HBr in acetic acid at room temperature or by hydrogenolysis. Alternatively, even a phosphoric amide may be used to afford an A-phos-phorylated product (221)" ... 

This problem was studied further by reacting chloroacetyl chloride with diethyl trimethylsilyl phosphite. In this case, the acylpseudophosphonium salt initially formed in the reaction contained a rapidly removable trimethylsilyl group. Indeed, the loss of chlorotrimethylsilane was rapid, allowing the formation of diethyl chloroacetylphosphonate (equation 16) ... 

Reaction of a,j5-unsaturated aldehydes with diethyl trimethylsilyl phosphite was used for the synthesis of chain-lengthened esters. Alkylation of the a-silyloxy-j ,y-unsaturated phosphonate with lithium diisopropylamide (Ida) and an alkyl halide occurs at the y-position with migration of the double bond to the a,j9-position. The silyloxyenolate could isolated in this reaction. Acide-catalysed alcoholysis leads to the carboxylic ester through the acylphosphonate (equation 93) ". ... 

Reactions between diethyl trimethylsilyl phosphite or tris(trimethylsilyl) phosphite and the appropriate 1,1-difluoroalkene yield the esters (279) and (280)(R = EtO or Me3Si). ... 

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