CHE 128A Study Guide - Final Guide: Protic Solvent, Steric Effects, Leaving Group
Document Summary
Sn1 and e1 have identical rate determining steps, so they generally occur simultaneously and have the same properties. mechanism big obstacle stereo- chemistry regio- chemistry rate expression. Sn1/e1 one step this single step is the rate-determining step (rds) Sn2: steric hindrance blocking nu (nu is in rds) E2: blocking b isn"t a big obstacle (b doesn"t join substrate) Sn2: inversion (backside attack, since lg blocks frontside) E2: cis vs. trans determined by anti-periplanar transition-state. E2: possible products from deprotonation of any -carbon major product w/ bulky base: less substituted (steric hindrance) major product with non-bulky base: more substituted. Sn2: methyl>1 >2 ; 3 gives no sn2 (substitutents block nu) E2: 1 , 2 , or 3 (blocking b is not a big obstacle) two steps rds is formation of carbocation stabilizing carbocation (nu/b isn"t in rds, so blocking it isn"t an obstacle) E1: both cis and trans isomers will be produced.
