Midterm 2 Study Guide

CHE201
Fall 2014
Dr. Diver

CHE201
Coverage: Chapters 5,6,7 (Carey)
(Note: No answer key will be published for this study guide. The concepts here are taken directly from the text, lectures, homework and problems in the book.)
Chapter 5 – Alkenes
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Be able to name alkenes
Be able to name alkenes using the E and Z nomenclature
Describe unique physical properties, hybridization of the alkene functional group
Understand the stabilities of alkenes, which provides the basis for Sayzeff’s rule
Alkenes are formed by elimination reactions. The main reaction was alcohol dehydration.
Elimination proceeds by defined regiochemistry
Be able to use Sayzeff’s rule to predict major products.
Why do E isomers predominate over Z isomers?
Discuss differences between E1 and E2 elimination
Understand and be able to write the complete reaction mechanism for alcohol dehydration
Be able to predict when a carbocation rearrangement may occur
Problems 5.45-5.47
Be able to draw a transition state for E2 dehydrohalogenation
Why is there an anti-periplanar requirement?
Be able to predict major product formation in E2 eliminations
Be able to draw chair conformational drawings of anti-elimination occurring in cyclohexyl halides, problems 5.43, 5.44
Define what an isotope effect is. What reaction displays isotope effects?
MAJOR REACTION SUMMARY
Alcohol dehydration (E1 mechanism), problem 5.38
Dehydrohalogenation of alkyl halides (E2 mechanism)
Predict the products, problem 5.41

Chapter 6 – Addition Reactions of Alkenes
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Alkene addition examples–hydrogenation, H2 addition, chirality centers can influence reaction (p. 219), hydrogen adds syn
Heats of hydrogenation – most stable alkene gives off less heat on hydrogenation; understand and be able to recall stability trend of alkenes.
HX addition-understand full reaction mechanism, apply Markovnikov rule to predict major products. Carbocation rearrangements are possible.
Problem 6.48
Acid-catalyzed hydration of alkenes (H2O addition)-know the entire mechanism, recognize reversibility and relationship to alcohol dehydration; follows Markovnikov’s rule

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CHE201
Fall 2014
Dr. Diver
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Hydroboration/oxidation-know reaction conditions, organoboron intermediate, stereochemistry of addition, concerted nature of the reaction, no rearrangements and the retention of stereochemistry in the oxidation step. Problem 6.40
Halogenation of alkenes proceed through halonium ion intermediates. Be able to draw intermediate, understand the stereospecific nature of the reaction, and understand the basis for halonium ion opening by halide via anti-attack.
Understand the mechanism and regiochemistry of halohydrin formation
Identify the reagent and predict the products of epoxidation
Identify the reagents and predict the products of ozonolysis
Be able to predict the product and write the mechanism for the HBR addition to alkenes using peroxides (or light)
Understand the concept of retrosynthetic analysis and be able to formulate a forward
synthesis.