Organomettalic Chemistry Y. B. Chavan College of Pharmacy Dr. K. G. Baheti Y. B. Chavan College of Pharmacy Rauza Bagh Aurangabad

Orano-metallic compounds are defined as compounds which possess more or less polar bond between metal and carbon atoms. In addition to traditional metals, lanthanides, actinides and other metals such as boran, silicon , arsenic and selenium forms organo-metallic compounds. Examples: Organo borane compound such as Triethyl borane Organo magnesium comp. such as Grignard reagent RMgX Organo copper comp. such as Alkyl copper lithium.

Organo borane compounds: These are the derivatives of BH3 (Boron trihydride) Organo borane compounds are important reagent, which enable many chemical transformation. The important tranformation is hydroboration reaction. Hydroboration reaction is the addition of boron(BH3) to double bond.

Organo borane compounds can be converted in to various products as mentioned below:

Another Organo borane compounds is borane tetrahydro furan complex H3B-THF, which is used for oxidation of alkene to alcohol with hydrogen peroxide and base.

What are Grignard reagents? A Grignard reagent has a formula RMgX where X is a halogen, and R is an alkyl or aryl (based on a benzene ring) group. For the purposes of this page, we shall take R to be an alkyl group. A typical Grignard reagent might be CH3CH2MgBr. Preparation of a Grignard reagent Grignard reagents are made by adding the halogenoalkane to small bits of magnesium in a flask containing ethoxyethane (commonly called diethyl ether or just "ether"). The flask is fitted with a reflux condenser, and the mixture is warmed over a water bath for 20 - 30 minutes. Everything must be perfectly dry because Grignard reagents react with water

Reactions of Grignard reagents Grignard reagents and water Grignard reagents react with water to produce alkanes. This is the reason that everything has to be very dry during the preparation above. For example: Grignard reagents and carbon dioxide Grignard reagents react with carbon dioxide in two stages. In the first, you get an addition of the Grignard reagent to the carbon dioxide. Dry carbon dioxide is bubbled through a solution of the Grignard reagent in ethoxyethane, made as described above. For example:

Grignard reagents and carbonyl compounds

Gilman Reagents When lithium dialkylcopper compounds, also known as Gilman reagents (after Henry Gilman), are converted by alkyl bromides, chlorides, or iodides, the cross-coupling products are obtained in good yields. Alkyl fluorides do not react with Gilman reagents. Gilman reagents can be synthesized through the treatment of the corresponding alkyllithium compound with copper(I) iodide in diethyl ether.

Applications

Organo-metallic Chemistry : What is meant by organometallic compounds and discuss about chemical reactions of Grignard reagents. What is organometallic compounds? Discuss the reactions of organomagnesium halide with: Aldehyde and Ketone Addition reactions with CO2, What is organometallic compound? Discuss reactions of organo-copper reagent. What is product of the reaction between ethyl magnesium bromide and acetone ? Write the structure of product.