Michael addition reacion

The Michael addition is a type of nucleophilic addition reaction in organic chemistry. It involves the addition of a nucleophile to an α,β-unsaturated carbonyl compound, such as an α,β-unsaturated ketone or aldehyde. This reaction is widely used to form carbon-carbon bonds in the synthesis of complex molecules.

 

General Reaction

1. A nucleophile (often an enolate or another nucleophilic species) attacks the β-carbon of the α,β-unsaturated carbonyl compound.
2. The product is a 1,4-addition product.

Example

Consider the reaction between an enolate (from acetone) and an α,β-unsaturated carbonyl compound (such as acrylonitrile):

1. Reactants:

   • Enolate of acetone: ${\text{CH}}_3{\text{COCH}}_2^{-}$
   • Acrylonitrile: ${\text{CH}}_2=\text{CH-C(CN)}$

2. Reaction:

   $${\text{CH}}_3{\text{COCH}}_2^{-}+{\text{CH}}_2=\text{CH-C(CN)}\to {\text{CH}}_3{\text{COCH}}_2-\text{CH}(\text{CN}){\text{CH}}_2$$

In this reaction, the nucleophilic enolate attacks the β-carbon of acrylonitrile, leading to the formation of a new carbon-carbon bond and giving the Michael addition product.

The Michael addition is a versatile and important reaction in organic synthesis, often used in the construction of complex molecules and natural products.