Scope
Conjugate addition is effective in the formation of new carbon-carbon bonds with the aid of organometallic reagents such as the organozinc iodide reaction with methylvinylketone.
An example of an asymmetric synthesis by conjugate addition is the synthesis of (R)-3-phenyl-cyclohexanone from cyclohexenone, phenylboronic acid, a rhodium acac catalyst and the chiral ligand BINAP.
In another example of asymmetric synthesis the α,β-unsaturated carbonyl compound first reacts with a chiral imidazolidinone catalyst and chiral auxiliary to an iminium compound in an alkylimino-de-oxo-bisubstitution which then reacts enantioselective with the furan nucleophile. The immediate reaction product is an nucleophilic enamine and the reaction cascades with abstraction of chlorine from a chlorinated quinone. 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.
This principle is also applied in an enantioselective multicomponent domino conjugated Addition of nucleophilic thiols such as benzyl mercaptan and electrophilic DEAD.
Read more about this topic: Nucleophilic Conjugate Addition
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