The coupling reactions

Coupling type reactions

3. Coupling Reactions:
Introduction:
•It is a general term for a variety of reactions in which two
fragments( Chemical Species) are joined together with
the help of different metal catalysts and different
conditions.
•For Example:
A main group organometallic compound of the type R-M;
where R stands organic fragment and M stands for main
group center , reacts with an organic halide of type R-X
with the formation of new C-C bond in the product R-R’.

4. Coupling Reaction

5. •Common metal used in this field is pd in addition to
Zn, Ni, Cu and Sn.
•Most of Coupling Reactions are Air and water
sensitive.
•But some coupling reactions can be carried out in
aqueous solutions.

6. There are two types of coupling reactions are
recognized on the basis of chemical species:
1.Homo-coupling Reactions
2.Hetero(Cross) coupling Reactions

7. 1. Homo Coupling Reactions:
•The reactions in which two identical chemical species are
combined to yield a single product.
Examples:
•Ullmann Reaction
•Wurtz Reaction
•Pinacol coupling Reaction
•Glaser coupling Reaction

8. The Glaser Coupling is a
synthesis of symmetric or
cyclic bis-acetylenes via a
coupling reaction of
terminal alkynes.
•This reaction involves
the reductive homo-
coupling of a carbonyl
compound to produce a
symmetrically
substituted 1,2-diol.

9. •Hetero coupling reactions are also called cross-
coupling reaction. The type of reaction in which two
dissimilar chemical species are joined together to
afford a single product.
Examples:
•Grignard Reaction
•Corey- House Synthesis
•Heck Reaction
•Suzuki Coupling
•The Buchwald-Hartwig Reaction

10. •The palladium-catalyzed C-C coupling between aryl halides or
vinyl halides and activated alkenes in the presence of a base is
referred as the "Heck Reaction".

11. •The Grignard reaction is an organometallic chemical
reaction in which alkyl, allyl, vinyl, or aryl-magnesium
halides is added to a carbonyl group in an aldehyde or
ketone. This reaction is important for the formation of
carbon–carbon bonds.

12. •Coupling Reactions are
employed in the synthesis of
several pharmaceutical
products.
•This type of reaction is used to
synthesize the conjugated
polymers by using metal
catalyst.
•Many natural compounds are
obtained by coupling reaction.