Arbusov rearrangement

To meet the needs of the advanced students, preparations have now been included to illustrate, for example, reduction by lithium aluminium hydride and by the Meerwein-Ponndorf-Verley method, oxidation by selenium dioxide and by periodate, the Michael, Hoesch, Leuckart and Doebner-Miller Reactions, the Knorr pyrrole and the Hantzsch collidine syntheses, various Free Radical reactions, the Pinacol-Pinacolone, Beckmann and Arbusov Rearrangements, and the Bart and the Meyer Reactions, together with many others. 

A Michaelis-Arbusov rearrangement followed by a Wittig-Horner reaction is involved in preparation of the distyrylbenzene derivative 11.37, as shown in Scheme 11.15. Precautions must be taken in the first stage to minimise formation of the carcinogenic by-product bis(chloromethyl) ether 11.16. The stilbene bis-ester 11.38 can be made by a similar procedure, or alternatively by the reaction of ethyl acrylate with 4,4 -dibromostilbene in the presence of a palladium-based catalyst (Scheme 11.16), a synthesis that yields the required trans form of the brightener. 

A-trityl-(l/ ,2S)-norephedrine (58), the corresponding allyl phosphonates 62a,b were obtained via the Arbusov rearrangement of 2-ethoxy-1,3,2-oxazaphospholidine 60. The absolute configuration of the major diastereomer, 62a was determined by X-ray as (2S1,45,51 ).The reaction of the major diastereomer of allyl phosphonates 61a and 62a with DBU afforded the corresponding vinylphosphonates 63a,b (Scheme 21) [48], Nucleophilic addition to these resulted in induction of chirality at the [1-position of the stereogenic phosphorus atom in the initially produced diastereomeric phosphonates 64 or 65 (Scheme 21) [48],... 

The dimethyl methylphosphonate (XI) can also be readily prepared by the Arbusov rearrangement of trimethyl phosphite 3... 

A. K. Bhattacharya u. G. Thyagarajan, The Michaelis Arbusov Rearrangement, Chem. Rev. 81, 415 (1980). A.N. Pudovik u. M.G. Zimin, Addition Reactions of partially-esterified Phosphorus Acids. Rearrangements of a-Hydroxyalkyl Phosphorus Esters and their a-Mercapto- and a-Amino-Analoges, Pure Appl. Chem. 52,989... 

The method described here for the preparation of diisopropyl methylphosphonate is a modification of the Arbusov rearrangement.4... 

Oligomers of phosphonate structure were formed in reaction and simultaneously transfer occurred as it could be expected for Arbusov rearrangement ... 

Phosphonic acid esters from phosphites Arbusov rearrangement... 

Scheme 7). Attempts at a similar Michaelis-Arbusov reaction using the butynyl chloride (55) unexpectedly gave 2-amino-6-chloro- -9-ethylpurine (56) as shown in Scheme 8. The photo-Arbusov rearrangement has been used as the key step in the syntiiesis of a series of acyclic... 

Methylene bis phosphinates (6.745e), with a central carbon chain, can be obtained from methyl phosphinic esters (6.253), or from methylphosphonous diesters, which, like phosphites, undergo Arbusov rearrangements with condensation (6.749). Methylene bis phosphinic acid can be obtained by reaction (6.750). This compound is reasonably stable in hot water, but on boiling it eventually gives methylene bis phosphonic acid, (H0)20P-CH2-P0(0H)2 [7]. 

Phosphonate complexes are liable to undergo Arbusov rearrangement to form phosphinates (9.133) and phosphite complexes may undergo similar rearranganent to phosphonates (9.134). The liability... 

It should be noted that aU phosphites reported are aryl phosphites (sometimes the backbones may be aliphatic) and that the favored ones often contain bulky substituents. One of the reasons that aliphatic phosphites are used only sparingly is that they are susceptible to the Arbusov rearrangement... 

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