Order of −I effect among ethenyl and 1-propenyl groups We know that both ethenyl $\ce{-CH=CH}_2$ and 1-propenyl $\ce{-CH=CH-CH3}$ are electron-withdrawing groups when attached to hydrocarbon chain. Which one has greater electron withdrawing power?
The $\ce{-CH3}$ is electron-donating, hence allyl should have lesser electron withdrawing effect. Is this correct?
I would say yes, the -CH3 group adds a little +I effect, making the -CH=CH-CH3 a little less electron withdrawing compared to the vinyl.