Α,β-Unsaturated Carbonyl Compounds. α,β-Unsaturated Carbonyl Compounds, reactions: 1.electrophilic addition deactivated 2.nucleophilic addition activated.

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Presentation transcript:

α,β-Unsaturated Carbonyl Compounds

α,β-Unsaturated Carbonyl Compounds, reactions: 1.electrophilic addition deactivated 2.nucleophilic addition activated 3.Michael Addition 4. Diels-Alder Reaction

1.electrophilic addition The carbonyl group is an electron withdrawing group when conjugated with a double bond. This decreases the electron density and deactivates the double bond to electrophilic addition.

2. nucleophilic addition The carbonyl group is an electron withdrawing group when conjugated with a double bond. This decreases the electron density and activates the double bond to nucleophilic addition.

3.Michael Addition. Carbanions as the nucleophiles in nucleophilic addition to α,β-usaturated carbonyls. (The enolate anion must be in reasonably high concentration for the Michael Addition to take place. Such enolates can be obtained from removal of alpha-hydrogens that are next to two electron withdrawing groups.)

4. Diels-Alder reaction: diene + dienophile  cyclohexene

α,β-Unsaturated Carbonyl Compounds, reactions: 1.electrophilic addition deactivated 2.nucleophilic addition activated 3.Michael Addition 4. Diels-Alder Reaction