For example, a double bond between the alpha and beta carbons of a carbonyl, is a conjugated system.
Normally, if an electrophile (electron lover) is added to an alkene, by Markovnikov’s rule, the electrophile will add on the carbon with least alkyl substituents [discussed ]. However, in the just said conjugated system, the electrophile may add to the carbonyl oxygen.
Another example, in the just said conjugated system, a nucleophile (likes to donate electrons) may add directly to the beta carbon, instead of adding to the carbonyl carbon [which is partially positive], as expected.
[img]conjugated-system-adding-anti-Markovnikovs.png[/img]