Arbuzov rearrangement mechanism

The phosphite esters function in this formulation as primary heat stabilizers by replacing labile chlorides on PVC via the Arbuzov rearrangement mechanism. When phosphites are used at optimized levels in combination with catalytic amounts of zinc and normal levels of epoxidized soybean oil, they provide excellent early color and adequate long-term stability to flexible PVC compounds. Their use also helps in lowering stabilization cost, elimination of toxic metals, elimination of plate out, poor printability, viscosity drift in plastisols, haze, bloom, water blush, and staining. 

Scheme 5 Photo-Arbuzov rearrangement of arylethylphosphites via a short-lived singlet proximate radical pair mechanism. Reprinted with permission from [22]. Copyright 2001 American Chemical Society...

Methoxy(methyl)(trifluoromethyl)phosphane (1) undergoes an Arbuzov rearrangement with iodomethane to give dimelhyl(trifluoromethyl)phosphane oxide (2). The reaction does not follow an intramolecular 1,2-shift mechanism, but rather occurs by the normal Arbuzov addition-substitution mechanism, as demonstrated by the reaction of 1 with iodomethane-phosphane oxide 2 containing a deuterated methyl group. 

Aksnes, G., Aksnes, D. Mechanism of the Michaelis-Arbuzov rearrangement in aceto- nitrile. Acta Chem. Scand. 1963,17, 2121-2122. 

The reaction is presumed to occur by initial formation of HjfMenO) PO], which then undergoes direct P-alkylation by nucleophilic attack of phosphorus on carbon with displacement of halide. An alternative alkylation mechanism involving nucleophilic attack of oxygen on carbon, followed by a Michaelis-Arbuzov rearrangement i) of a dialkyl phenylphosphonite (C6H5(MenO)POR) intermediate with the alkyl halide was effectively eliminated by the observation that reaction of methyl phenylphosphinate with a tenfold excess of methyl-c/3 iodide gave the product distribution shown in Eq. (2). 

Abramov, V.S., and ITina, N.A., Mechanism of the Arbuzov rearrangement. Part 3. Reaction of the nitrile and methyl ester of a,P-dibromo- and a,P-dichloropropionic acids with phosphites, Zh. Obshch. Khim., 26, 2014, 1956 Chem. Abstr., 51, 1822c, 1957. 

A paper on new approaches to the generation of arylphosphinidenes has been published. The stable bis-azide precursor (133) upon photolysis, or vapour phase thermolysis, gave (134), obviously via the phosphinidene (135) the same product was obtained by photolysis of the phosphaketene (136). The reduction of aryldiazonium salts to arenes with triethyl phosphite or triphenylphosphine is shown to proceed by a radical-chain mechanism. The previously described photo-Arbuzov rearrangement of benzyl phosphites has been used to prepare several acyclic phosphonate nucleotide analogues, e.g. (137). ... 

Phosphorus. Reactions of three-co-ordinate phosphorus(m) compounds generally involve associative mechanisms, as in exchange at (Me2As)2P(CF3), in the reaction of phosphines with hydroxide, and of trialkyl phosphites with hypochlorite. In the last case, the phosphorus appears to be five-co-ordinate in the transition state. The reaction sequence for trialkyl phosphites plus phosphorus trifluoride includes a Michaelis-Arbuzov rearrangement. The first stereochemical study of reactions of phosphorus(iii) compounds with radicals demonstrates retention of configuration this result is consistent with more than one possible mode of reaction. Further examples of reactions of phosphorus(iii) compounds appear later, when analogous derivatives of phosphorus(m) and phos-phorus(v) are compared. 

The mechanism of the Arbuzov rearrangement of (allyloxy)phosphines PhJP-(0C3H5)34 (n = 0-2) at room temperature catalysed by [CpRu(AN>3]PF4 has been investigated. A new procedure has been developed for the preparation of enantiomerically pure sulphoxides and ruthenium complexes such as [CpRu((X>)(FI%3)(t-BuMeSO)]SbF4 by a combination of asymmetric oxidations of dialkylsulphides and metal resolution of the products. The Diels Alder reaction of coordinated dienophiles in [CpRu(dnq]p)3 (dienophile)JPF( have been investigated for a range of complexes. ... 

Pudovik AN. Mechanism of the Arbuzov rearrangement. Dokl. Akad NaukS.S.S.R. 1952 84 519-522. 

The mechanism of the Perkow reaction has been a subject of some debate but is now generally thought to proceed by initial attack of phosphorus at the carbonyl carbon atom, not by rearrangement of a Michaelis-Arbuzov intermediate 5.77,78... 

Many different mechanisms have been proposed for the Perkow reaction.2-4 It involves nucleophilic attack of the phosphite at the carbonyl carbon and affords a zwitterionic intermediate 5 which rearranges to form a cationic species 6 that subsequently dealkylates to give the corresponding vinyl phosphate 7. The conversion proceeds via a Michaelis-Arbuzov cleavage of an alkoxy group by halide ion as shown. 

A simple and efficient route to a variety of structures containing phosphorus-carbon bonds, under mild conditions and in good chemical yields, has been developed by Michalski and co-workers. Halotrimethylsilanes MesSiX (X = Br, I) catalyzed rearrangements of tricoordinate phosphorus esters (584) into the corresponding phosphoryl systems (585) (Scheme 144). Experimental evidence indicated that the mechanisms of the reactions were fundamentally different from that of the Michaelis-Arbuzov reaction. 

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