N-Propylmagnesium bromide explained

n-Propylmagnesium bromide, often referred to as simply propylmagnesium bromide, is an organomagnesium compound with the chemical formula . As the Grignard reagent derived from 1-bromopropane, it is used for the n-propylation of electrophiles in organic synthesis.[1]

Properties

Like all Grignard reagents, propylmagnesium bromide is a strong electrophile, sensitive to both water and air.

The propylmagnesium halides are the simplest Grignard reagents to exhibit isomerism. Isopropylmagnesium chloride is the primary synthetic equivalent of the isopropyl group.[1]

n-Propylmagnesium bromide is soluble in ether, tetrahydrofuran, and toluene.[2]

Synthesis

Synthesis is analogous to other saturated alkyl Grignard reagents. A solution of 1-bromopropane in ether - typically diethyl ether or tetrahydrofuran - is treated with magnesium, which inserts itself into the organohalogen bond. As both the magnesium metal and the product are sensitive to water, the reaction must take place in anhydrous conditions.[3]

While the product is often portrayed as simply, in reality it will quickly form a tetrahedral coordination complex with the Lewis basic solvent, centred on the magnesium atom:

Applications

Propylmagnesium bromide is used in the Grignard reaction to introduce propyl groups to nucleophiles.[1]

Notes and References

  1. Maruyama . Kazuhiro . Matano . Yoshihiro . Katagiri . Toshimasa . Product-determining factors in the grignard reactions of benzophenones. The role of the structure of alkyl groups in grignard reagents . Journal of Physical Organic Chemistry . August 1991 . 4 . 8 . 501–515 . 10.1002/poc.610040806.
  2. Book: Macintyre . Jane E. . Dictionary of Organometallic Compounds . 10 November 1994 . CRC Press . 978-0-412-43060-2 . 2275 . en.
  3. Canonne . P. . Foscolos . G. . Caron . H. . Lemay . G. . Etude de l'influence du diluant hydrocarbone dans la reaction des organomagnesiens primaires sur les cetones encombrees . Tetrahedron . January 1982 . 38 . 24 . 3563–3568 . 10.1016/0040-4020(82)80061-6.