enter image description here

Shouldn't the exocyclic alkene (Hofmann) be the major product? The base is $\ce{t-BuO-}$ (tertiary butoxide ion), which is pretty bulky. I think the Saytzeff product should be the minor product.

Also, the solution says "E2, some E1". It's a 3° alkyl halide (more sterically hindered than 1° and 2°), so shouldn't it undergo E1 elimination?

  • $\begingroup$ You have reasoning already in your picture. Also don't put "thanks" in posts. You can do it in comments. $\endgroup$ – Mithoron Jun 29 '17 at 15:58
  • $\begingroup$ I don't understand the reason given, according to that E1 Hoffman elimination should be favoured. Please explain. $\endgroup$ – arya_stark Jun 29 '17 at 16:19
  • $\begingroup$ "good base" for mechanism, high temp - isomer $\endgroup$ – Mithoron Jun 29 '17 at 16:28
  • $\begingroup$ The base is sterically hindered. $\endgroup$ – arya_stark Jun 29 '17 at 16:51
  • $\begingroup$ Maybe it would matter matter in low temp. $\endgroup$ – Mithoron Jun 29 '17 at 16:55

Yup, $\ce{t-BuO-}$ is a bulky base.

But is it bulky enough that it can't even abstract a hydrogen from the ring? Nope.

Take a look at this picture of a $\ce{t-BuO-}$ molecules approaching the hydrogen of 1-bromo-1-methyl-cyclopentane.

enter image description here

Does that $\ce{t-BuO-}$ look like it's struggling to pull that hydrogen out? Definitely not. It's doing what it does with ease.

  • 2
    $\begingroup$ The picture given in the question states some conditions. What do you think about their relevance to the Zaitsev Product? $\endgroup$ – Mockingbird Jun 30 '17 at 6:58

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