Nucleophilic conjugate addition

With α,β-unsaturated carbonyl compounds such as cyclohexenone it can be deduced from resonance structures that the β position is an electrophilic site which can react with a nucleophile.

The negative charge carried by the nucleophile is now delocalized in the alkoxide anion and the α carbon carbanion by resonance.

Conjugate addition is effective in the formation of new carbon-carbon bonds with the help of organometallic reagents such as the organozinc iodide reaction with methylvinylketone.

After removal of the amine catalyst the ketone is effectively functionalized with a nucleophile and an electrophile with syn:anti ratio of 8:1 and 97% enantiomeric excess.

[3] This principle is also applied in an enantioselective multicomponent domino conjugated addition of nucleophilic thiols such as benzylmercaptan and electrophilic DEAD.