E1
Introduction
Introduction
The E1 mechanism is an elimination reaction , hence the E. The 1 stands for unimolecular.
Reagents/Reaction Conditions
Reagents/Reaction Conditions
Substrate: 3˚>2˚>>1˚, allylic and benzylic
Solvent: polar protic is best.
Weak base
Neutral to acidic
Heat
3D Sense
3D Sense
Regioselectivity: Zaitsev major
Stereoselectivity: trans major
Mechanism
Mechanism
There are two core steps (in bold) and two other possible steps in an E1 reaction:
Proton transfer
Loss of leaving group
Carbocation rearrangement
Proton transfer
The slow (rate-determining step) is the loss of the leaving group, which only has one reactant (the substrate), hence the unimolecular in the reaction name.
The reaction of tert-butyl alcohol with concentrated H2SO4 (aq.) and heat
This reaction has the following steps:
Proton transfer
Loss of leaving group
Proton transfer