And Zaitsev’s rule

In some cases, especially wdth cyclic compounds, the more stable alkene forms and Zaitsev s rule applies. For example, menthyl acetate gives 35% of... 

The mechanism is usually E2. Hofmann s rule is generally obeyed by acyclic and Zaitsev s rule by cyclohexyl substrates (p. 1315). In certain cases, where the molecule is highly hindered, a five-membered Ei mechanism, similar to that in 17-7, has been shown to operate. That is, the OH in these cases does not attract the P... 

In some cases, especially with cyclic compounds, the more stable olefin forms and Zaitsev s rule applies. For example, menthyl acetate gives 35% of the Hofmann product and 65% of the Zaitsev, even though a cis (3 hydrogen is present on both sides and the statistical distribution is the other way. A similar result was found for the pyrolysis of menthyl chloride.138... 

Keep in mind that the major product of an E2 reaction is the more stable alkene, and Zaitsev s rule is just a shortcut to determine which of the possible alkene products is the more substituted alkene. The more substituted alkene is not, however, always the more stable alkene. In the following reactions, the conjugated alkene is the more stable alkene even though it is not the most substituted alkene. The major product of each reaction is, therefore, the conjugated alkene because, being more stable, it is more easily formed. 

Keep in mind that the major product of an E2 reaction is the more stable alkene, and Zaitsev s rule is just a shortcut to determine which of the possible alkene products is the... 

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