Phosphites with carbonyls

Sekine, M., Yamamoto, I., Hashizume, A., and Hata, T., The reaction of tris(trimethylsilyl) phosphite with carbonyl compounds, Chem. Lett., 485,1977. 

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 detailed kinetic study of the reaction of trialkyl phosphites (44) with benzil has been carried out (see Chapter 2 for the reactions of a-diketones with trialkyl phosphites). The reaction is first-order in both phosphite and benzil and the rate constant increases with the dielectric constant of the solvent. The authors propose initial attack of phosphite at carbonyl carbon (45), in opposition to the original suggestion by Ramirez, who proposed initial attack at carbonyl oxygen. 

Olefination Reactions Involving Phosphonate Anions. An important complement to the Wittig reaction involves the reaction of phosphonate carbanions with carbonyl compounds 253 The alkylphosphonic acid esters are made by the reaction of an alkyl halide, preferably primary, with a phosphite ester. Phosphonate carbanions are generated by treating alkylphosphonate esters with a base such as sodium hydride, n-butyllithium, or sodium ethoxide. Alumina coated with KF or KOH has also found use as the base.254... 

Preparation of 2,2,2-trimethoxy-3-phenyl-4-acetyl-5-methyl-A4-oxaphospholene — Preparation of an oxyphosphorane by reaction of a trialkyl phosphite with an a,(l-unsaturated carbonyl compound... 

Kharasch, M.S. and Bengelsdorf, I.S., The reaction of triethyl phosphite with a-trichloromethyl carbonyl compounds, /. Org. Chem., 20, 1356, 1955. 

Okamoto, Y. and Azuhata, T., The reaction of diethyl acyl phosphites with a,P-unsaturated carbonyl compounds, Bull. Chem. Soc. Jpn., 57, 2693, 1984. 

Phosphoniutn ylides can be generated by treatment of diazoacetates and triphe-nylphosphine or triethyl phosphite with catalytic amounts of RuCl2(PPh3)2 [ 1343] or ReOCl3(PPh3)2 [1344]. If these reactions are conducted in the presence of aldehydes, carbonyl olefination takes place in high yields. 

When the ratio of template to acid is close to 0.5, the viscosity of the product is more than 3 times higher than the viscosity of the polymer obtained without the template. PEO participates in the change of local concentration by interaction with carbonyl groups, but not in the activation. Solution of LiCl in N-methylpyrrolidone with PlOCeHsls was found very effective system for synthesis of amides by the direct reaction of acids with amines in the presence of polymeric matrix. High molecular weight poly(aminoacids) obtained by direct polycondensation reaction, promoted by triphenyl phosphite and LiCl in the presence of poly(vinylpyrrolidone), were synthesized by Higashi et al The results for polymerization of L-leucine in the presence of poly(vinyl pyrrolidone) are presented in the Table 6.3. 

However, difluoromethylation occurs when nucleophiles intercept difluoro-carbene generated under basic conditions, providing a route to difluoromethyl-ethers of phenols [33] and thiophenols [34]. The reaction with phosphite anion leads to the corresponding difluoromethyl phosphonate (see Sect. 2.3.2) while nucleophilic carbanions such as alkynes [35] also undergo formal alkylation, as do malonates [36,37]. An -difluoromethylaziridine was reported in a reaction with a glycine imine [38]. The scope of the established chemistry is summarised in Fig. 1. Bromodifluoromethylation occurs with a similar range of nucleophiles [39,40], and also with carbonyl-stabilised carbanions such as malonates [41,42]. 

A possible explanation of these differences is that the reactions of the trivalent phosphorus compounds with carbonyl compounds may contain reversible and irreversible steps. The condensation of one mole of biacetyl with one of the phosphite probably contains several reversible steps leading eventually to the 1 1 oxyphosphorane. If this 1 1 adduct is of high energy as a result of ring strain and/or intramolecular crowding in the TBP, it might not be observable. The carbon-carbon condensation step in the formation of the 2 1 adducts is probably essentially irreversible under most conditions hence, once that step is achieved, there is an opportunity for isolation of the 2 1 phosphoranes. 

There is direct experimental evidence, in the case of the reactions of phosphites with pentafluorobenzaldehyde,111,112 (45)+ (46), for the reversible attack by the phosphorus of phosphite on the carbonyl-carbon.112 At some latter stage, there is attack of phosphorus on... 

The reaction of a silyl phosphite with an a-haloaldehyde or ketone generally leads to a 1 1 adduct (i.e. addition at the carbonyl carbon atom to yield a silyloxyphosphonate by the Abramov reaction, cf. Section 5). However, both the Perkow and the Michaelis-Arbuzov pathways are significant and frequently dominate, the outcome depending on the nature of the reactants and the reaction conditions.47... 

The spectra and kinetics of the reaction of LFe(CO)4 (L = phosphines and phosphites) with organomagnesium halides are consistent with nucleophilic attack on the carbonyl group trans to the axial phosphine ... 

Tetrakis(triaryl phosphite)nickel(O) and tetrakis(trialkyl phosphite)nickel(O) complexes have been prepared by the reaction of the desired phosphite with nickel carbonyl under forcing conditions and by the reaction of bis(cyclopenta-dienyl) nickel with the desired phosphite in an aromatic solvent. The present procedure is similar to the last-mentioned method. 

A facile procedure for highly regioselective and efficient synthesis of cx-hydroxyphosphonates (274) and (275) based on the reaction of trialkyl phosphites with epoxides in LiC104/Et20 has been presented (Scheme 70). p-Hydroxyalkylphosphonates (276) have been prepared under neutral conditions by reaction of diethyl iodomethylphosphonates (277) and carbonyl... 

Finally, carbohydrate ligands of enantioselective catalysts have been described for a limited number of reactions. Bis-phosphites of carbohydrates have been reported as ligands of efficient catalysts in enantioselective hydrogenations [182] and hydrocyanations [183], and a bifunctional dihydroglucal-based catalyst was recently found to effect asymmetric cyanosilylations of ketones [184]. Carbohydrate-derived titanocenes have been used in the enantioselective catalysis of reactions of diethyl zinc with carbonyl compounds [113]. Oxazolinones of amino sugars have been shown to be efficient catalysts in enantioselective palladium(0)-catalyzed allylation reactions of C-nucleophiles [185]. 

The reagent is prepared by treating the half-ester of maleic acid with triethyl phosphite and converting the product into the phosphonate carbanion by stirring with a slurry of 50% sodium hydride in 1,2-dimethoxyethane. The carbanion reacts with carbonyl compounds like a Wittig ylide but is more reactive. 

Examples of the reaction of tervalent phosphorus with isocyanates and their analogues include the addition of phosphites to carbonyl isothio- and isoseleno-cyanates to give the phosphonates (32) and the reaction of dialkyl phosphoramidites with trichloroacetyl isocyanate to give the rearranged product (33). Predictably, the betaine (34) is obtained from the reaction of TDAP with fluorosulphonyl isocyanate more surprising is the relative stability of (34) to hydrolysis. ... 

Sekine, M., Okimoto, K., Yamada, K., and Hata, T., Silyl phosphites. Part 15. Reactions of silyl phosphites with a-halo carbonyl compounds. Elucidation of the mechanism of the Perkow reaction and related reactions with confirmed experiments, J. Org. Chem., 46. 2097. 1981. 

Herzig, C., and Gasteiger, J., Reaction of 2-chlorooxiranes with phosphites and phosphanes. A new ronte to (l-carbonylphosphonic esters and -phosphonium salts, Chem. Ber., 115, 601, 1982. Krentzkamp, N., and Kayser, H., Carbonyl- and cyanophosphonic esters. Part 2. The course of reaction of phosphites with bromo- and chloroacetone, Chem. Ber, 89, 1614, 1956. 

Griffiths, D.V., Jamah, H.A.R., and Tebby, J.C.. Reactions of phosphites with acid chlorides. Phosphite attack at the carbonyl oxygen of a-kctophosphonates. Phosphorus Sulfur, 11, 95, 1981. 

Kreutzkamp, N., and Kayser, H., Carbonyl- and cyanophosphonic esters. Part 2. The course of reaction of phosphites with bromo- and chloroacetone, Chem. Ber., 89, 1614, 1956. 

Synthesis of labeled phosphonoacetates proceeds on heating trialkyi phosphites with methyl or ethyp5 [l- C]bromoacetate, methyl [2- C]bromoacetate, ethyl [2- C]bromoacetate, ethyl [2- C]bromoacetate, and methyl or ethyl[ l- C]bromoacetate. Dialkyl l-(methoxy-carbonyl)methyl[l,l- H2]phosphonates are prepared from trialkyi phosphites and ethyl [2,2- H2]bromoacetate ° or by simple treatment of the nondeuterated phosphonoacetate with H2O in the presence of K2(X),." 5... 

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