Textbook: Carey and Giuliano 8th Ed. (2010)

Chapter 5: Structure and Preparation of Alkenes: Elimination Reactions

Practice Problems and Mendel Sets

Individual Problems

Problem # 518
 

The alcohol below is protonated and contains an oxygen with a positive charge. Using curved arrows, show the two "legal moves" that result in a neutral oxygen.

Problem # 519
 

Let's work through an elimination reaction. Draw the structures for each of the species in the three boxes below (protonated thiol, carbocation, and alkene). Also draw curved arrows to show electron movement. 

Problem # 333

Let's go over how a carbocation can form from an alcohol.

Write in the curved arrows to show the formation of the protonated alcohol, and water acting as a leaving group to form a carbocation.

Problem # 335

Carbocations aren't very stable and so don't last very long after they are formed.

Use curved arrows to show:

a) how a carbocation reacts with a halide ions to form an alkyl halide.

b) how a carbocation reacts with water to form an alcohol.

c) how a carbocation reacts with a base to form an alkene.

Problem # 348

For the reaction below, draw the structures of the carbocation intermediate and the final product.

Problem # 531

 

E2 elimination reactions require anti-coplanar geometry. (note: some textbooks call this anti-periplanar).
Let's work through an E2 reaction, and rotate the molecule eblow into an anti-coplanar geometry to predict the product of this E2 reaction.

 

Problem # 319

For a molecule to undergo an E2 reaction, the leaving group and the beta-proton must be in an anti-coplanar conformation (one atom straight up, the other straight down). Based on this, which compound undergoes E2 reaction with KOtBu faster? Why?

 

Problem # 341
 

 Predict the product(s) of the reaction below, and used curved arrows to show a mechanism.

Mendel Sets

MS 899 - Beginning Mechanism Practice Submitted by Matt on August 6, 2011.

Textbook and Chapters: Carey and Giuliano 8th Ed. (2010), Chapters 4, 5

Keywords: carbocation rearrangement, free radical halogenation, mechanism

Description: Practice mechanisms from the first half of Fall semester orgo. Dehydration (E1), substitution with carbocation rearrangement (SN1), and free-radical bromination.

Total Problems: 3

MS 903 - Carbocation and Alkene Review Drills Submitted by Matt on August 6, 2011.

Textbook and Chapters: Carey and Giuliano 8th Ed. (2010), Chapters 4, 5, 6

Keywords: alkene addition, carbocation

Description: Identify the intermediates (carbocation, radical, borane intermediate, etc.) and products for important reactions dealing with alkenes. Good review for an orgo1 midterm.

Total Problems: 7

MS 904 - Carbocation Drills Submitted by Matt on August 6, 2011.

Textbook and Chapters: Carey and Giuliano 8th Ed. (2010), Chapters 4, 5, 6

Keywords: carbocation, carbocation formation, carbocation rearrangement

Description: This mendel set guides you through everything you have to know about carbocations:

  • Ways carbocations form
  • Carbocation rearrangements
  • How carbocations react (elimination or nucleophilic attack)

Also includes some practice problems: addition to an alkene, dehydration (E1), and substitution (SN1).

Total Problems: 8