E1cB Reaction
An elimination reaction that happens when a compound bearing a poor leaving group
and an acidic hydrogen is treated with a base.
E1cB stands for Elimination Unimolecular conjugate Base. The reaction is
unimolecular from the conjugate base of the starting compound, which in turn is
formed by deprotonation of the starting compound by a suitable base.
The electron withdrawing group (EWG) can be a carbonyl group (keto, aldehyde,
ester), a nitro group, an electron deficient aromatic group etc. Dehydration of aldol is
the most common E1cB reaction
With strong sterically hindered bases: Elimination occurs by an E2 mechanism
With weak nucleophiles or bases: A mixture of SN1 and E1 products results