Substitution at sp3 Carbon 5: Allylic and Benzylic Substitution
Channel: Oxford College Chemistry Courses: Scharf
Date: 2023-06-06

In this video, we explore why SN1 and SN2 reactions are especially fast at allylic and benzylic sites, due to resonance stabilization of carbocations (for the SN1 reaction) and transition state conjugation (for the SN2 reaction). We also introduce why SN1 reactions of allylic substrates often give mixtures of products.

Expert Note: We discuss kinetic vs. thermodynamic control for allylic substitution in the subsequent course (in the context of addition across conjugated dienes). See the video Conjugation 5 at https://youtu.be/DhgJy2iCvDQ.