Zaitsev's Rule

Zaitsev’s or Saytzev’s (anglicized spelling) rule is an empirical rule used to predict regioselectivity of 1,2-elimination reactions occurring via E1 mechanism or via E2 mechanism. It states that in a regioselective E1 or E2 reaction the major product is the more stable alkene, i.e., the alkene with the more highly substituted double bond.

eg:

E1 reaction always follow Zaitsev’s rule; with E2 reactions, there are exceptions (see antiperiplanar).

see also Hofmann rule

Contributors

• Gamini Gunawardena from the OChemPal site (Utah Valley University)