[mana]

hi all
in the elimination reaction (E2) below which alkene prefer as the product due to zaitsev rule?

[Babcock_Hall]

As I am confident has been said previously, it is a Forum Rule (see red link near the top of the page) that you supply your answer or at least provide your thoughts before we can help you.  A good place to start is to identify which of the choices is in accord with Zaitsev's rule, and which choice is not.  A nice addition to this would be an articulation of at least one reason why Zaitsev's rule is not always followed.

[mana]

As I am confident has been said previously, it is a Forum Rule (see red link near the top of the page) that you supply your answer or at least provide your thoughts before we can help you.  A good place to start is to identify which of the choices is in accord with Zaitsev's rule, and which choice is not.  A nice addition to this would be an articulation of at least one reason why Zaitsev's rule is not always followed.

I asked this question because I realy don't know the answer btw 2 alkenes as product with the same number of substituents, or the conditions that zaitesev rule is not followed

[Babcock_Hall]

I agree that both are tri-substituted and do not appear different from the point of view of Zaitsev's rule.  Having written many homework and test questions, I can say that this question might have been a mistake (they happen fairly regularly), or it might be that an answer to the effect that they are equally likely as products might be the expected answer.  One could use some form of computational chemistry to explore the relative stabilities of the two alkenes, but that is probably not part of the present exercise.  One other thing that I find odd about this problem is that it does not specify which base is used.  In some eliminations, that is an important choice in the hands of the experimenter, although it is not obvious to me that it would make any difference in this example.

[mana]

I agree that both are tri-substituted and do not appear different from the point of view of Zaitsev's rule.  Having written many homework and test questions, I can say that this question might have been a mistake (they happen fairly regularly), or it might be that an answer to the effect that they are equally likely as products might be the expected answer.  One could use some form of computational chemistry to explore the relative stabilities of the two alkenes, but that is probably not part of the present exercise.  One other thing that I find odd about this problem is that it does not specify which base is used.  In some eliminations, that is an important choice in the hands of the experimenter, although it is not obvious to me that it would make any difference in this example.

thank you