PROFILPELAJAR.COM

Grignard reagent

Grignard reagents are a type of chemical compound. They are used in the Grignard reaction, an important tool used in organic synthesis to make new chemical bonds between carbon atoms.

Grignard reagents have three parts: an organic group, written as R, a magnesium atom, and a halogen atom written X. The chemical formula for a Grignard reagent is written RMgX. These reagents are normally a coordination complex with solvent molecules, not a pure solid, so the formula is also sometimes written including them. For example, a solution of methylmagnesium chloride in tetrahydrofuran could be written CH3MgCl(THF)2.

Preparation

Grignard reagents are normally made from an organohalide and magnesium metal. The normal reaction mechanism starts with a single electron transfer from the magnesium atom to the organohalide, which breaks apart into a halide anion and an organic radical. The radical then bonds with the Mg+ radical cation, finishing the reagent.[1]

For example, the reaction of chloromethane and magnesium:

CH3Cl + Mg → ·CH3 + ·Mg+ + Cl− → CH3MgCl

Reactions

Grignard reagents RMgX are normally treated as equivalent to the R− carbanion. They are very strong nucleophiles and bases, and will react with any source of hydrogen ions to make an alkane and magnesium salts. This means they cannot be used in protic solvents like water.

The most important reaction for Grignard reagents is the Grignard reaction. In this reaction, they react with electrophilic carbon atoms in carbonyl compounds, making magnesium alkoxides. A workup with water normally changes the alkoxide into an alcohol.

Sources

  1. ↑ "Formation of Grignard Reagents from Organic Halides". University of Texas.

Content Disclaimer

Informasi ini disarikan dari Wikipedia dan disajikan kembali untuk tujuan edukasi. Konten tersedia di bawah lisensi CC BY-SA 3.0. Kami tidak bertanggung jawab atas ketidakakuratan data yang bersumber dari kontribusi publik tersebut.

  1. The information displayed on this website is sourced in part or in whole from Wikipedia and has been adapted for the purpose of restating it. We strive to provide accurate and relevant information, however:
  2. There is no guarantee of absolute accuracy. Wikipedia is an open, collaborative project that can be edited by anyone, so information is subject to change.
  3. It is not intended to constitute professional advice. The content displayed is for informational and educational purposes only. For important decisions (e.g., medical, legal, or financial), please consult a professional.
  4. Content copyright. Wikipedia is licensed under the Creative Commons Attribution-ShareAlike License (CC BY-SA). This means that content may be reused with appropriate attribution and shared under a similar license.
  5. Responsible use. Any risk arising from the use of information from this website is entirely the responsibility of the user.