Chapter 15: An Introduction to Organometallic Compounds
Table of Contents:
Organomagnesium and Organolithium Compounds
Reactions Of Grignard And Organolithium
Lithium Diorganocopper (Gilman) Reagents
Carbenes and Carbenoids
Organomagnesium and Organolithium Compounds
Organomagnesium (Grignard reagent) has a formula of RMgX where X is Br, Cl or I.
Organolithium has a formula of R-Li.
Making Grignard And Organolithium
To make Grignard reagent, we must start with an alkyl halide where the halogen is Br, Cl or I. We then react it with Mg/ether.
Product: Replace X with MgX
To make organolithium reagent, we must start with an alkyl halide where the halogen is Br, Cl or I. We then react it with 2Li.
Product: Replace X with Li
Reactions Of Grignard And Organolithium
Both Grignard and organolithium compounds are very strong acids and will get protonated in the presence of H2O, ROH or any acid.
In the first example, Grignard reagent is reacting with water. MgBr is replaces by H.
In the second example, Organolithium reagent is reaction with alcohol. In this case, instead of H alcohol has D, deuterium which is an isotope of hydrogen. Li gets replaced by D in the product.
Reactions of Grignard and Organolithium with Epoxide
An epoxide will react with either Grignard reagent or Organolithium reagent.
Product: Get rid of the epoxide, and attach OH to the most substituted carbon
from the epoxide and R on the least substituted carbon from the epoxide. (attach carbon that was attached to MgX and what is it connected to).
Mechanism for the reaction of epoxide with Grignard reagent.
How to predict the reactants from the epoxide + RMgBr (RLi) product
Mayya's Trick
Break the bond between C with OH and the least substituted carbon it is attached to
Attach MgBr or Li to the carbon broken
Remove H from OH and attach O to the neighboring carbon making an epoxide
Lithium Diorganocopper (Gilman) Reagents
Making Gilman Reagent
We need to start with 2R-Li and react it with CuI with either diethyl ether or THF.
Product: (R)2CuLi
Vynilic Halide Reaction with Gilman Reagent
Vinilyic halide is a molecule that has a halogen attached to the double bond.
Product: Get rid of the halogen and attach the carbon that was connected to halogen to the carbon from 1 R group from (R)2CuLi. The configuration of the carbon carbon double bond is preserved
Epoxide with Gilman Reagent Reaction
Product: Get rid of the epoxide, and attach OH to the most substituted carbon from the epoxide and R (only 1) on the least substituted carbon from the epoxide.
Carbenes and Carbenoids
Carbenes are highly reactive and behave as electrophiles.
Making Carbenes and Carbene Reaction
