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Markovnikov ruleZoomA-Z

Subject - Organic Chemistry

The rule formulated in 1869 by V.V. Markovnikov (also Markownikoff) predicts the products of an electrophilic addition of asymmetrical reagents (e.g. hydrogen halides, water and alcohols) to asymmetric alkenes. It states that the reaction favors the formation of the regioisomer in which the more electrophilic part of the reagent has been added to the carbon atom of the double with the most hydrogens. The logic behind the Markovnikov rule is the understanding that in a two-step electrophilic addition the electrophile adds to the double bond in such a way that the more stable carbenium ion is formed as intermediate.

An addition product in which the addition occured opposite to the one predicted by the Markovnikov rule is called an anti-Markovnikov product. Mostly, this occurs inradical additions and also during hydroborations.

See also: Markovnikov product

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