Dehydration Zaitsev elimination

Zaitsev s rule as applied to the acid catalyzed dehydration of alcohols is now more often expressed in a different way elimination reactions of alcohols yield the most highly substituted alkene as the major product Because as was discussed in Section 5 6 the most highly substituted alkene is also normally the most stable one Zaitsev s rule is sometimes expressed as a preference for predominant formation of the most stable alkene that could arise by elimination... 

In E2 elimination, dehydration proceeds most readily when the two groups to be eliminated have an anti periplanar relationship. In this compound, the only hydrogen with the proper stereochemical relationship to the -OH group is at C6. Thus, the non-Zaitsev product 3-methylcyclohexene is formed. 

When an alcohol has two or three different P carbons, dehydration is regioselective and follows the Zaitsev rule. The more substituted alkene is the major product when a mixture of constitutional isomers is possible. For example, elimination of H and OH from 2-methyl-2-butanol yields two constitutional isomers the trisubstituted alkene A as major product and the disubstituted alkene B as minor product. 

Alcohols undergo dehydration in concentrated sulfuric or phosphoric acid. These elimination reactions follow Zaitsev s rule, yielding the more substituted alkene as the major product. 

Zaitsev s rule as applied to the acid-catalyzed dehydration of alcohols is now more often expressed in a different way elimination reactions of alcohols yield the most highly... 

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