Phosphinite esters

Preparation of l,10-diphenyl-l,10-diphosphacyclooctadecane 1,10-dioxide — Reaction of an alkyl halide with a phosphinite ester generated in situ by reduction of a phosphinate... 

Apart from their properties as ligands, other aspects of the reactivity of phosphinite esters have been of interest. It has been shown that phosphinite esters (77) undergo the Michaelis-Arbuzov rearrangement to give the phosphine oxides (78) between room temperature and 80°C in the presence of trimethylsilyl halides, the reaction not needing the presence of any alkyl halide. The rearrangement proceeds even more efficiently at room temperature in the... 

Similar reactions with phosphinite esters have recently been reported (265) the major products are the S-bromoethylphosphine oxides. However, the only product isolated from interaction of 1,2-dibrom-propane with triethyl phosphite was diethyl 1-propene-l-phosphonate in poor yield (103). 

It has recently been demonstrated in our own laboratory that negatively substituted olefins of the type known as dienophiles react smoothly with phosphite, phosphonite, and phosphinite esters in the presence of a suitable proton donor (123,127). With the use of phenol for this purpose, reactions are exceptionally clean and high yields may be realized. Some representative examples are included in Table I. While ethanol or methanol are often satisfactory substitutes for phenol, the yields of phosphonate are generally lower and side reactions often occur, possibly due to the lessened efficiency of alcohol as a protonating agent. Yields of phosphonate for reactions in ethanol are indicated in brackets in Table I. Thus, in addition to the expected phosphonate from reaction of acrylamide and triethyl phosphite in ethanol, there were also ob-... 

It has already been indicated that the course of any reaction may depend, to some extent, on the nature of the phosphite (or phosphonite) ester (phosphinite esters yield phosphine oxides). Thus, tris(perfluoroalkyl) phosphites do not undergo a Michaelis-Arbuzov reaction with perfluoroiodoalkanes, although reports on the outcome of any reaction between triethyl phosphite and CF3I, under normal conditions, are conflicting reactions do appear to proceed under photostimulation. A normal reaction does take place at high temperatures between polyfluorinated trialkyl phosphites and methyl iodide, when the product, MeP(0)(0Rf)2, is accompanied by oxidation of the phosphite to phosphate Either elimination or alkylation accompanies the formation of unidentified phosphorus-containing products in the reactions between trialkyl phosphites and the halides Cl3C(CF2) Cl n - 2, 4 or 6) ... 

Reactions between haloketones and phosphonite esters, R P(OR)2, produce enol esters of phosphonic acids or esters of the phosphinic acids, R (R C0CH2)P(0)0R, depending on the halogen involved whilst phosphinite esters, R2POR yield the phosphinic acid esters R2P(0)0CPh=CHBr when treated with a,a-dibromoacetophenone . ... 

Unsymmetrical tertiary phosphine oxides can be prepared by heating some phosphinite esters (6.115), by reaction of organolithium derivatives with alkyl halides (6.116) or by oxidation with H2O2 (6.117). Tertiary phosphine oxides are produced in Arbusov (3.108), Wittig (3.111) and many other reactions (6.66-6.73), (6.383), (6.388), (6.422), (6.427, 6.526). 

Rhodium chelates of some vicinal bis-diphenylphosphinite sugar derivatives have been used in asymmetric catalytic hydrogenation, and a further study of similar compounds concluded that ee s were dramatically improved when electron donating aryl phosphinite esters were used. The synthesis and properties of the 1,3,6-phosphite of 2,4-di-f>-nielb -p-D-glucopyranose has been described, and 1 1 complexes have been observed between octyl a- and D-ghico-, manno-, and galacto-pyranosides and the phosphonales 21 and 22. 

Degtyarev, A. N. Godovikov, N. N. Bregadze, V. I. Matrosov, E. I. Shcherbina, T. M. Kabachnik, M. I. 1978. Synthesis and chemical properties of some carboranylmethyl-phosphinite esters. Izv. Akad. Nauk SSSR, Ser. Khim. 2099-2104. 

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