Arbuzov reactions

Olefin Metathesis and Metathesis Polymerization, Academic Press, London, 1997. 

The Arbuzov reaction,also called the Michaelis-Arbuzov reaction, allows for the synthesis of pentavalent alkyl phosphoric acid esters 4 from trivalent phosphoric acid esters 1 (Z,Z = R,OR) by treatment with alkyl halides 2. 

Most common is the preparation of alkyl phosphonic acid esters (phospho-nates) 4 (Z,Z = OR) from phosphorous acid esters (phosphites) 1 (Z,Z = OR). The preparation of phosphinic acid esters (Z = R, Z = OR) from phosphonous acid esters, as well as phosphine oxides (Z,Z = R) from phosphinous acid esters is also possible. 

The reaction mechanism outlined below for phosphorous acid esters analogously applies for the other two cases. The first step is the addition of the alkyl halide 2 to the phosphite 1 to give a phosphonium salt 3  

This intermediate product is unstable under the reaction conditions, and reacts by cleavage of an 0-alkyl bond to yield the alkyl halide 5 and the alkyl phos-phonate 4  

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The phosphonates obtained by the Arbuzov reaction are starting materials for the Wittig-Homer reaction (Wittig reaction), for example, appropriate phosphonates have been used for the synthesis of vitamin A and its derivatives/... 

Important and widely used variants of the Wittig reaction are based on carbanionic organophosphorus reagents, and are known as the Wadsworth-Emmons reaction, Wittig-Horner reaction or Horner-Wadsworth-Emmons reaction. As first reported by Horner, carbanionic phosphine oxides can be used today carbanions from alkyl phosphonates 13 are most often used. The latter are easily prepared by application of the Arbuzov reaction. The reactive carbanionic species—e.g. 14 —is generated by treatment of the appropriate phosphonate with base, e.g. with sodium hydride ... 

Several benzothiazinone analogs have been synthesized in an attempt to introduce hetero substituents at the a-carbon center in these heterocyclic compounds. The required a-halo-benzothiazinone intermediate 148 was prepared by chlorination with sulfiiryl chloride. This material was used successfully in an Arbuzov reaction to prepare the phosphonate diester 149,... 

Three- and pentacoordinate organic phosphorus compounds can be oxidized through a free radical Arbuzov reaction, i.e., formation and p-scission of a phosphoranyl radical (Scheme 24). The P-scission is regioselective homolysis occurs on a ligand located in an equatorial site. Both a- and P-scissions are strongly dependent on the strength (bond dissociation energy) of the cleaved... 

The free radical Arbuzov reaction has been developed for the preparation of vinyl- and arylphosphonates in good to excellent yields. Oligonucleotides, suitably modified in the vicinity of the phosphorus backbone to impart nuclease... 

Scheme 36 Preparation of vinylphosphonates via free radical Arbuzov reaction...

In this context, the treatment of the AT-phosphinyl iminoethers 15 with methyl iodide furnish the P-methyl phosphonium iodides, which by heating experience an 0-dealkylation, reminiscent of the Arbuzov reaction, for yielding the iV-acylphosphazenes 16 [45] (Scheme 16). 

The reaction with phosphite esters is known as the Michaelis-Arbuzov reaction and proceeds through an unstable trialkoxyphopsphonium intermediate. The second stage is another example of the great tendency of alkoxyphosphonium ions to react with nucleophiles to break the O—C bond, resulting in formation of a phosphoryl P—O bond. 

An Arbuzov reaction between gem-dibromocyclopropanes yields phosphonate esters (55) accompanied by debrominated compounds successful reaction requires the presence of traces of water (and is thus not the normal Arbuzov reaction) which, by studies with D2O, has been shown to supply the a-proton of (56), Normal Arbuzov reactions, using ethyl diphenyl phosphite, have been used to prepare a phosphonate isostere of B-D-arabinose-1,5-diphosphate. ... 

An adaptation of the Arbuzov reaction (Scheme 14) using the hydrazones of 1-chloroalkyl ketones provides a route to dialkyl (2-oxoalkyl)phosphonates (79 R =Me, C1CH2, Ph, EtOOCCH2, or (Et0)2P(0)CH2 R2=H, generally R3=MeO, EtO).73... 

As shown in Equation (23), the 3-chloromethyl-l,2,4-oxadiazole 159 (X = H) undergoes Arbuzov reaction to give the phosphonate 148 which has been used in Wadsworth-Emmons reactions as shown previously in Equation (21) <1989J(P1)2047>. 

Preparation of tris(trimethylsilyl) phosphite — Preparation of a silyl ester of a trivalent phosphorus acid for Michaelis-Arbuzov reaction... 

The well-known Michaelis-Arbuzov reaction is historically the fundamental approach to generating C-P bonds using a neutral trivalent... 

Figure 3.3 Adamanyl esters in the Michaelis-Arbuzov reaction. 

A wide variety of reagents have been found to undergo the Michaelis-Arbuzov reaction in a facile manner. Established approaches toward the generation of new C-P bonds using this variety of reagents are briefly summarized in the following ... 

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