Do both elimination reactions, E1 and E2, follow Zaitsev’s rule?

1 Answer
Jul 14, 2015

#"E1"# eliminations follow Zaitsev's rule. With two exceptions, #"E2"# reactions also follow Zaitsev's Rule.


(1) Certain cyclohexane derivatives.

Some cyclohexane derivatives, such as menthyl chloride, form the Hofmann product instead:


Formation of the Zaitsev product requires antiperiplanar elimination at the 2-position, but the isopropyl group – not the proton – is in the antiperiplanar location.


But there is an antiperiplanar hydrogen at the 6-position, so elimination occurs there and produces only the Hofmann product.

(2) Bulky bases

Bulky Base

A bulky base attacks the least sterically hindered proton to form the Hofmann product.