Question

ii) The rates of Diels-Alder reaction of the compounds below are compare with that of 1,3butadiene. Please explain the trend. CH3 H3C CH VCH3 H нс faster Slower similar to butadiene

Answer 1

First of all, s-cis conformation is more reactive in Diels Alder reaction. Because of this reason , cyclopentadiene is more reactive since it has s-cis conformation (fixed).

And then electron releasing groups like alkyl group increases the reactivity of diene .

Of alkyl substituents are on central carbons , reactivity is more compared to on Terminal carbons of diene which is less reactive due to steric crowd.

First diene is too less reactive due to steric crowd