Redox reactions enone reduction

Reaction of die organocuprate intermediate widi water gives the fully reduced product. If die organocuprate intermediate is reacted widi bromine, the a-brominated product is formed. This product has die equivalent oxidation level as the starting enone but differs in that an additional carbon substituent is present. Functionally this is equivalent to the addition of HBr to an enone. Thus functionally no net redox has taken place. If individual steps are considered, it is clear that the first step (addition of the organocuprate to die enone) is a reduction and the second step (reaction of the cuprate with bromine) is an oxidation. 

Friedel-Crafts reactions. The reaction of osmium-complexed anisoles with electrophiles such as enones is catalyzed by TfOH. Benzylation of arenes by a reductive alkylation with arenecarbaldehyde acetals involves an intramolecular redox process (hydride shift) after protonation of the benzylic ether intermediates. 

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