E1 & E2 briefly reviewed Identify everything wrong in the statements below below: 1) Dehydration of an alcohol to make alkynes via E2 Makes alkenes no alkynes Via E1 2) Both E1 and E2 involve a protonated alcohol and both undergo rearrangement Only E1 involves protonated alcohol and rearrangement 3) Dehydrohalogenation runs E1 and converts alkenes to halohydrins using CCl4 solvent Runs E2 converts alkyl halides to alkenes with KOH in ethanol

*3a,3b are both 3o so are termed  sites. *1 is 1o hence a  site 2 1,2 and 3a are all  sites 3b is an  site 5) E2 involves a secondary isotope effect at the -H and uses KOH as a solvent Involves a primary isotope at -H Uses ethanol as solvent (KOH is reagent) 6) E2 elimination of 2-bromobutane starts with the bromine receiving a lone pair from OH- Starts with -H on 2-bromobutane forming a bond with OH- to make water

7) E1 elimination of an alcohol to form an alkenes requires the alcohol to have at least one -H Not so. A carbocation can undergo methyl shifts and subsequently could make an alkene 8) E2 elimination of 2-bromobutane forms just one product alkene according to Zaitsev’s rule NO. two products form: one major and one minor 9) The rate-limiting step in E1 elimination of ROH to alkenes is the alcohol protonation step No…the carbocation formation step where ROH2+ R+ + H2O is is the rate limiting step

Tennis ball pass U-PICK Which Mechanism(s) apply 0) dehydration of ROH to alkene E1 E2 Primary H effect E1 E2 2) H+ catalyzed E1 E2 3) Rearrangements occur E1 E2 4) Base driven E1 E2 5) -H always necessary E1 E2

U-PICK Which Mechanism(s) apply U-PICK Which Mechanism(s) apply (continued) 6) Products obey Saitsev rule E1 E2 7) Reaction rate order: 3o>2o>1o E1 E2 8) Involves a carbocation E1 E2 9) Involves a 4-atom electron flow E1 E2 10) More than one product alkene possible E1 E2 11) Competes with substitution reaction E1 E2

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