To use all functions of this page, please activate cookies in your browser.
With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
Additional recommended knowledge
The reaction was discovered by Michaelis in 1898, and greatly explored by Aleksandr Arbuzov soon thereafter. This reaction is widely used for the synthesis of various phosphonates, phosphinates, and phosphine oxides. Several reviews have been published.
The Michaelis-Arbuzov reaction is initiated with the SN2 reaction of the nucleophilic phosphite (1) with the electrophilic alkyl halide (2) to give a phosphonium intermediate (3). Triaryl phosphites, which are unable to perform the second step of the Michaelis-Arbuzov reaction, have been shown to produce stable phosphonium salts. Likewise, aryl and vinyl halides are unreactive towards phosphites.
The displaced halide anion reacts via another SN2 reaction with the phosphonium intermediate to give the desired phosphonate (4) and another alkyl halide (5). When chiral phosphonium intermediates are produces, it has been shown the halide substitution proceeds with inversion of configuration, as expected by a SN2 reaction.
As a general guideline, the reactivity of the organic halide (2) can be listed as follows: (from most reactive to least reactive)
RCOX > RCH2X > RR'CHX >> RR'R"CX
RI > RBr > RCl
The Michaelis-Arbuzov reaction of α-bromo- and α-chloroketones does not give the expected product. This side reaction is called the Perkow reaction. α-Iodoketones do, in fact, give the expected phosphonate. Other methods of producing β-ketophosphonates have been developed.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Michaelis-Arbuzov_reaction". A list of authors is available in Wikipedia.|