CHM 2120 Lecture Notes - Lecture 12: Benzyl Group, Weak Base, Elimination Reaction
3 Nov 2016
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Document Summary
The biggest clue to an sn1 reaction is a carbocation that is slow to form and a rate determining slow step. The solvent acts as the nucleophile and bonds with the carbocation. To identify an sn1: a carbocation, conjugate base of solvent substituted the leaving group. 2 steps: 1) leaving group leaves a carbocation (rds) Polar aprotic solvent eg. dmsa: nucleophile attack causing leaving group to leave all in one step. Clues: no carbocation, nucleophile subsitutes carbon, faster reaction. Leaving group breaks and we get a carbocation. Nucleophile attacks the neighboring hydrogen, leaving a double bond. One step reaction, no formation of carbocation, fast reaction. Primary carbocations are very unstable so they will not form. But if a primary carbocation has a double bond near it, it can share the electrons so that will be very stable. Also, if a primary carbocation is attached to a benzyl ring, it can resonate.
