Its four subtypes include ip and R, in which the departure of the leaving group is rate-limiting.
Its four subtypes include ip and R, in which the departure of the leaving group is rate-limiting. For aryl phenylacetates and other esters with acidic alpha-hydrogens, this mechanism is preferred over the Bac2 mechanism for acyl transfer. The transition from the enolate to the final product of the Knoevenagel reaction proceeds via this mechanism. Samarium oxide and other rare earth oxides are good catalysts for this mechanism, which is highly selective for the Hofmann orientation. In the final step of the Robinson annulation, the transition between the beta-hydroxyketone and the alpha, beta-unsaturated ketone is a dehydration that follows this mechanism. Reactions of alkyl halides proceed via this mechanism if the leaving group is two carbons away from a carbonyl group. It usually takes place in a strong base, and in this mechanism, the departure of the leaving group occurs after a charged intermediate is generated by the abstraction of a proton. For 10 points, name this type of elimination mechanism featuring a carbanion intermediate.
Its four subtypes include ip and R, in which the departure of the leaving group is rate-limiting.
E1cb (unimolecular elimination via conjugate base)