Michaelis–Arbuzov reaction

The Arbuzov reaction or Michaelis- Arbuzov reaction [ often found in alternative spelling (English ) Transkiption Arbusov ] is a name reaction in organic chemistry. It was named after the Russian chemist Alexander Jerminingeldowitsch Arbuzov (Russian: Александр Ерминингельдович Арбузов, 1877-1968 ) and the German chemist August Michaelis ( 1847-1916 ). By reacting a nucleophilic compound with a trivalent phosphorus haloalkane a pentavalent phosphorus compound is obtained with a new phosphorus -carbon bond.

The Arbuzov reaction proceeds by an SN2 mechanism. The starting material is prepared by alkylation at the trivalent phosphorus initially with the quaternary phosphonium salt. By attack of the nucleophilic counterion to an alkoxy group, this little stable intermediate converts the elimination of an alkyl halide in the more stable pentavalent phosphorus compound to:

Another driving force is the often occurring during the reaction by distillation removal of the resulting alkyl halide from the reaction equilibrium. In effect, you will often result of alkyl chlorides (X = Cl) and phosphorus compounds with ethoxy groups (-O -R = -O- C2H5), so that the highly volatile chloroethane is a by- product ( R -X).

Depending on the nature of Y and Z is different, products are obtained:

With Y and / or Z = -S-R the sulfur analogs can be obtained. Mention an example parathion. Generally, this reaction for the preparation of insecticides and banned under the Geneva Conventions nerve agents ( sarin, tabun ) are used. The chemistry of the phosphoric acid ester was decisively influenced by Gerhard Schrader.

In addition, this reaction is an important process for the production of reagents for the Horner-Wadsworth -Emmons reaction.