Triphenylphosphite, reaction

Rydon and co-workers (73) have shown that the reaction of simple alcohols with triphenylphosphite methiodide and triphenylphosphite dihalides gives alkyl halides according to the general scheme. 

In addition to simple halides, the method was used to prepare chol-esteryl iodide (30%) and cyclohexyl iodide (34%) from the corresponding alcohols, thus demonstrating the applicability of the reaction to cyclic secondary alcohols. An early adaptation to carbohydrates was reported by Lee and El Sawi (75). They claimed that treatment of l,2 5,6-di-0-isopropylidene-D-glucofuranose (49) with triphenylphosphite methiodide... 

The reaction is quite susceptible to steric effects since hindered secondary hydroxyl groups were found to be unreactive. The method can therefore be used to selectively replace a primary hydroxyl group by halogen in the presence of more hindered secondary hydroxyl groups in the same molecule. An example (70) is the reaction of 52 with triphenylphosphite methiodide which affords the 6-deoxy-6-iodo derivative 53 (60%) in which the C-2 hydroxyl group remains intact. 

In a similar way, 5-O-acetylthymidine was converted into the 3-deoxy-3-iodo derivative 72 in 55% yield. In this case, the replacement of the hydroxyl group by iodine was presumed to have taken place by retention of the configuration at C-3. The first intermediate in the reaction was proposed to be the phosphonate (70) which rapidly collapses to an O-3-cyclonucleoside (71) and the latter is subsequently attacked by iodide ion to give the product 72. It was also observed (106) that treatment of nucleosides containing a cis vicinal diol grouping such as 5-0-acetyluridine with triphenylphosphite methiodide failed to provide iodinated products but gave phosphonate derivatives instead. 

Very subtle ligand effects have been detected in these reactions. Thus, under the same conditions, 1 mole of tricyclohexylphosphine and 1 mole of Ni(COD)2 in the presence of excess morpholine catalyze addition of acetophenone to 2 moles of butadiene to give compound A below, whereas triphenylphosphine gives B. With triphenylphosphite C—C coupling no longer occurs, but morpholine adds to butadiene to give C (135). 

Iodotrimethylsilane formed in situ from the reaction of chlorotrimethylsilane and sodium iodide, also effects the conversion of 2-ene-l,4-diols to 1,3-dienes (equation 16)46. Allylic thionocarbonates on heating with triphenylphosphite undergo deoxygenation (Corey-Winter reaction) to generate olefins47. This procedure has been used for making hexatrienes (equation 17)47b. 

The first iridium catalysts for allylic substitution were published in 1997. Takeuchi showed that the combination of [fr(COD)Cl]2 and triphenylphosphite catalyzes the addition of malonate nucleophiles to the substituted terminus of t -allyliridium intermediates that are generated from allylic acetates. This selectivity for attack at the more substituted terminus gives rise to the branched allylic alkylation products (Fig. 4), rather than the linear products that had been formed by palladium-catalyzed allylic substitution reactions at that time [7]. The initial scope of iridium-catalyzed allylic substitution was also restricted to stabilized enolate nucleophiles, but it was quickly expanded to a wide range of other nucleophiles. 

Although most of these early reactions were conducted with allylic acetates, reactions of allylic carbonates, trifluoroacetates, and phosphates also occur. Sodium diethylmalonate also reacts with allylic alcohols in the presence of the iridium-triphenylphosphite catalyst. However, the alcohol itself does not act as a leaving group. Instead, transesterification occurs with one equivalent of malonate nucleophile to form a more labile ester leaving group. 

Addition to linear 1,1-disubstituted allylic acetates is slower than addition to monosubstituted allylic esters. Additions to allylic trifluoroacetates or phosphates are faster than additions to allylic carbonates or acetates, and reactions of branched allylic esters are faster than additions to linear allylic esters. Aryl-, vinyl, alkynyl, and alkyl-substituted allylic esters readily undergo allylic substitution. Amines and stabilized enolates both react with these electrophiles in the presence of the catalyst generated from an iridium precursor and triphenylphosphite. 

We then studied the reactions of CH3Mn(CO)5 with triphenylphosphine and triphenylphosphite, using the same solvent, tetrahydrofuran. In these cases the observed rate constant rose with ligand concentration towards a limiting value, which was close to the rate constant obtained using cyclohexylamine (Figure I). 

Figure J. Reaction of CH Mn(CO) with triphenylphosphite in tetrahydrofuran plot of observed rate constant against triphenylphosphite concentration.

We believe this is the case for the reactions of CH3Mn(CO)5 with triphenylphosphine and triphenylphosphite in tetrahydrofuran. 

If the mechanism is correct, Equation 7 shows that a plot of the reciprocal of the observed rate constant against the reciprocal of the ligand concentration should be linear for the reactions of CH3Mn(CO)5 with triphenylphosphine and triphenylphosphite. This was found to be the case for both reactions (Figure J), and provides good evidence that the postulated mechanism is indeed correct. 

K. Kefurt, J. Jary, and Z. Samek, Reaction of methyl 2,3-O-isopropylidene-ot-L-rhamno-pyranoside with triphenylphosphite methiodide, J. Chem. Soc. Chem. Commun. p. 213 (1969). 

There are a few syntheses outside the reaction categories discussed in the previous sections. Enol ether 71 was successfully transformed into the desired 1,2-dioxetane 72 (25%) utilizing triphenylphosphite ozonide, even though it contains a disulfide bond which would be of great susceptibility to further oxidation (Equation 4) <2002JA4874>. 

Phenols are transformed into aryl chlorides by PhPCl4779. Aromatic and aliphatic aldehydes give, in high yields, gem dibromides with combination of triphenylphosphite and bromine780. Brominative deoxygenation of ketones is achieved by 2,2,2-tribromo-l,2,3-benzodioxaphosphone781. Allylic alcohols are transformed into allylic iodides by reaction with P2I4782. 

The photoinduced reaction of the contact ion pair Cp2Co+ Co(CO)4 takes a third course when the triphenylphosphine or tributylphosphine additive is replaced with triphenylphosphite, namely,... 

It has already been shown that the nitration with nitric acid in acetic anhydride provides the general way of obtaining /V-ni trohctcrocyclcs. As an alternative synthesis of the aforementioned compounds, and, in particular, 1-nitrobenzotriazole, the reaction of 1-chlorobenzotriazole with the silver nitrate-triphenylphosphite complex can be suggested [273],... 

The Step 1 product (1.37 g Mn 26,000 daltons), 4-aminobenzoic acid (2.24 mmol), triphenylphosphite (5 mmol), and LiCl (0.09 g) were dissolved in 30 ml A-methyl-pyrroUdinone/pyridine solution, 80 20, and heated to 100°C for 4 hours. The reaction mixture was then precipitated in an excess of water/methanol, 1 1, fdtered, and washed with methanol. The material was dried overnight under vacuum at 40°C, and the product was quantitatively isolated. 

Liu and co-workers have elaborated [137] a highly efficient method for the synthesis of spiroimidazolinones 99 via a microwave-assisted three-component one-pot domino reaction of a protected amine, an amino acid ester and a carboxylic acid in the presence of triphenylphosphite in pyridine, providing the desired... 

Though largely unstudied, it has recently been shown that Ir-catalyzed allylic substitution reactions where a strong n-acceptor ligand, for example, triphenylphosphite, is present... 

Various polyesters derived from phosphorous or phosphoric acids were prepared. Efiicient polyphosphites were synthesised in the early 196(. Polyphosphite prepared from 152 and 4,4 -isopropylidenebis(cyclohexanol) was tested as a thermal stabilizer for PC [199] or as secondary AO for radiation sterilized EPM [200]. Built-in phosphites obtained by transesterification of triallcylphosphite with 4,4 -isopro-pylidenebisphenol or 4,4 -thiobisphenol possess antioxidant properties in polyolefins. Stabilizer containing phosphite moiety 153 was prepared from tris(2-hydroxy-ethyl)isocyanate, decyl alcohol and triphenylphosphite [201]. Various phosphites were derived firom polynuclear phenols or dihydric phenols. For example, a polycondensate prepared by reaction of phosphorus trichloride with 2,5-di-rert-butylhydroquinone was tested as heat and light stabilizer for PP [202], A linear polyester with a built-in phenolic moiety was synthesised from (2,6-di-tm-butyl-4-methylphenyl)bis(6-hydroxyhexyl)phosphite and dimethyl terephthalate [203]. 

The coupling reaction between phenol and ethylene to give ortho-ethylphenol is catalyzed by (triphenylphosphite)ruthenium complex [20]. In this reaction, the ortho C-H bond of triphenylphosphite is cleaved by orthometallation, and then insertion of ethylene followed by reductive elimination lead to the formation of triarylphos-phite having an ortho-ethylphenoxo group. Transesterification between the phosphite and phenol then releases (ortho)-ethylphenol by reproducing triphenylphosphite (Scheme 14.8). 

This e c o-peroxide rearranged readily to form the /ra s-benzene trioxide 144 and gave trans-benzene dioxide 142 upon reaction with triphenylphosphite. A similar addition reaction occurred between singlet oxygen and indan 8,9-oxide 7 to yield a further endo-peroxide. An endo-peroxide adduct of an oxepin was also formed when singlet oxygen reacted with 1-benzoxepin 100. Upon deoxygenation with trimethylphosphite, the latter peroxide yielded an aldehyde. ... 

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