Wurtz reaction

The Wurtz synthesis (or Wurtz reaction ) is a name reaction in organic chemistry, which was discovered in 1854 by Adolphe Wurtz. It is used for synthesis of ( cyclo) alkanes from haloalkanes.

Overview reaction

In the reaction, there is a coupling of two alkyl halides to alkanes symmetrical.

As the reducing agent sodium is most commonly used. The radicals R are alkyl groups.

Mechanism

The exact details of the mechanism of the reaction have not been elucidated so far. There is however a currently accepted mechanism is as follows:

First, the haloalkane reacts with sodium to form a carbanion organometallic compound. In the second step, the alkyl group of the metalated compound as nucleophile attacks of another haloalkane. There is a nucleophilic substitution of the halide.

The reactivity of haloalkanes, decreasing in the order alkyl iodides, bromides and Alklylchloride. The driving force of Wurtzschen synthesis is the formation of a sodium halide with high lattice energy.

Use

Because of side reactions such as eliminations or rearrangements preparative use of Wurtzschen synthesis is severely limited.

• An example, but in which the yields are about 90 %, the structure of strained systems:

• By means of Wurtzschen synthesis are cycloalkanes the ring size from three to six carbon atoms accessible:

• Squalene is an acyclic Triterpenkohlenwasserstoff, which was first isolated in 1916 from Tsyjimoto from cod liver oil of sharks. The synthetic production runs using the Wurtz synthesis with magnesium: