Question 1

These compounds have very different acidities. State which is the most acidic, which is the least acidic, which is in the middle, and why.

Accepted Answer

Each of the compounds contains an allylic proton. The allylic protons in compound A are double allylic since it is next to two double bonds. The resulting carbanion can be delocalized to give a stable carbanion.
   Compound B contains two equivalent allylic protons. There are only two resonance structures possible.
   Compound C also contains a doubly allylic proton. In addition, the resulting carbanion results in an aromatic ring, which is very stable. The charge can be delocalized to each carbon in the ring.
   The most acidic compounds will have the most stable conjugate base. Thus, compound C is the most acidic, followed by compound A, then compound B.

Question 2

The compound was synthesized from MnO2 oxidation. Deduce the structure of the starting material.

Accepted Answer

Manganese dioxide oxidizes allylic alcohols to aldehyde or ketones, so the ketone must have been an alcohol.

Question 3

A bottle labeled 3-iodo-1-pentene (structure below) was stored in the back of the laboratory refrigerator. Several weeks later, a chemist analyzed the compound and found that it was contaminated with a different molecule with the same molecular formula. Determine the structure of the isomer and draw a curved-arrow mechanism to explain how it was formed.

Accepted Answer

3-Iodo-1-pentene contains an allylic iodide. Loss of the iodide leaving group leaves a secondary carbocation, which has a resonance structure with a primary carbocation.
   The iodide ion can attack resonance structure 1 to regenerate 3-iodo-1-pentene, or it can attack resonance structure 2 to form 1-iodo-2-pentene.
   Note, the 1-iodo-2-pentene is the thermodynamic product since it is a disubstituted alkene, as compared to 3-iodo-1-pentene, which is a monosubstituted alkene.

Question 4

Determine the major organic product for the reaction.

Accepted Answer

Potassium permanganate will oxidize benz

Question 5

Determine the major organic product for the reaction.

Accepted Answer

There is only one be

Question 6

Propose a multistep synthesis for the compound from toluene. You may assume that ortho and para isomers can be separated as necessary. Reaction mechanisms are not necessary.

Accepted Answer

Working backwards, the carboxylic acid p

Question 7

Determine the major organic product for the reaction. The product should have a molecular formula of C10H13Br.

Accepted Answer

N-bromosuccinimide (NBS) is used to conv

Question 8

Draw the major organic products for the reactions.

Accepted Answer

The starting material contains two benzy

Question 9

Rationalize these two observations through analysis of intermediates.
1. Solvolysis of bromocyclopentene in methanol is much faster than is solvolysis of bromocyclopentane.
2. Solvolysis of bromocyclopentadiene is slower than solvolysis of bromocyclopentane.

Accepted Answer

For each alkyl halide, consider the stab

Question 10

In each set of reactions, circle the one that occurs faster.
a. 
   b.

Accepted Answer

a. Both reactions are eliminations. In t

Question 11

The structure of geraniol is shown. Label the allylic carbons with an asterisk (*).

Accepted Answer

An allylic carbon is a carbon

Question 12

Carvone is a terpenoid that is found in essential oils and used for aromatherapy. Highlight the isoprene units in carvone and classify the terpene based on the number of carbons (ex. monoterpene, etc.)

Accepted Answer

Carvone contains two isoprene

Question 13

Which substrate will undergo the reaction the fastest?
$\mathrm { RBr } \stackrel { \mathrm { NaOCH } _ { 3 } } { \longrightarrow } \mathrm { ROCH } _ { 3 } + \mathrm { NaBr }$

Accepted Answer

A)  compound A 
B)  compound B 
C)  compound C 
D)  compound D 
A)  compound A 
B)  compound B 
C)  compound C 
D)  compound D

Question 14

Consider these alcohols and explain whether oxidation with pyridinium chlorochromate (PCC) and MnO2 would give the same product, different products or no reaction.

Accepted Answer

PCC will oxidize primary alcohols to ald

Question 15

Humulene is a terpene that is responsible for the hops aroma in beer. Highlight the isoprene units in humulene and classify the terpene based on the number of carbons (ex. monoterpene, etc.)

Accepted Answer

Humulene consists of three iso

Question 16

Determine the major organic product for the reaction.

Accepted Answer

Since the bromination reaction occurs in

Question 17

Which of these compounds is the most acidic?

Accepted Answer

A)  compound A 
B)  compound B 
C)  compound C 
D)  compound D 
A)  compound A 
B)  compound B 
C)  compound C 
D)  compound D

Question 18

Determine the major organic product for the reaction.

Accepted Answer

Alkyl benzenes are oxidized us

Question 19

Consider the structure of eugenol, which is commonly found in essential oils and is used in perfumes.
  Which statement is true?

Accepted Answer

A)  Eugenol contains an allylic carbon and no benzylic carbons. 
B)  Eugenol contains a benzylic carbon and no allylic carbons. 
C)  Eugenol contains both an allylic and a benzylic carbon. 
D)  Eugenol does not contain an allylic nor a benzylic carbon. 
A)  Eugenol contains an allylic carbon and no benzylic carbons. 
B)  Eugenol contains a benzylic carbon and no allylic carbons. 
C)  Eugenol contains both an allylic and a benzylic carbon. 
D)  Eugenol does not contain an allylic nor a benzylic carbon.

Question 20

Draw the major organic product for the reaction.

Accepted Answer

Manganese dioxide will only ox

Exam 17: Allylic and Benzylic Reactivity

These compounds have very different acidities. State which is the most acidic, which is the least acidic, which is in the middle, and why.

The compound was synthesized from MnO2 oxidation. Deduce the structure of the starting material.

Determine the major organic product for the reaction.

Determine the major organic product for the reaction.

Propose a multistep synthesis for the compound from toluene. You may assume that ortho and para isomers can be separated as necessary. Reaction mechanisms are not necessary.

Determine the major organic product for the reaction. The product should have a molecular formula of C10H13Br.

Draw the major organic products for the reactions.

Rationalize these two observations through analysis of intermediates. 1. Solvolysis of bromocyclopentene in methanol is much faster than is solvolysis of bromocyclopentane. 2. Solvolysis of bromocyclopentadiene is slower than solvolysis of bromocyclopentane.

In each set of reactions, circle the one that occurs faster. a. b.

The structure of geraniol is shown. Label the allylic carbons with an asterisk (*).

Carvone is a terpenoid that is found in essential oils and used for aromatherapy. Highlight the isoprene units in carvone and classify the terpene based on the number of carbons (ex. monoterpene, etc.)

Which substrate will undergo the reaction the fastest? RBr⟶NaOCH3ROCH3+NaBr\mathrm { RBr } \stackrel { \mathrm { NaOCH } _ { 3 } } { \longrightarrow } \mathrm { ROCH } _ { 3 } + \mathrm { NaBr }RBr⟶NaOCH3​​ROCH3​+NaBr

Consider these alcohols and explain whether oxidation with pyridinium chlorochromate (PCC) and MnO2 would give the same product, different products or no reaction.

Humulene is a terpene that is responsible for the hops aroma in beer. Highlight the isoprene units in humulene and classify the terpene based on the number of carbons (ex. monoterpene, etc.)

Determine the major organic product for the reaction.

Which of these compounds is the most acidic?

Determine the major organic product for the reaction.

Consider the structure of eugenol, which is commonly found in essential oils and is used in perfumes. Which statement is true?

Draw the major organic product for the reaction.

Chemical Bonding and Chemical Structure

Alkanes and Organic Nomenclature

The Curved-Arrow Notation, Resonance, Acids and Bases, and Chemical Equilibrium

Introduction to Alkenes and Alkynes

Addition Reactions of Alkenes and Alkynes

Principles of Stereochemistry

Cyclic Compounds and Reaction Stereochemistry

Nomenclature and Noncovalent Intermolecular Interactions

The Chemistry of Alkyl Halides

Free-Radical Reactions, Main-Group Organometallic Compounds, and Carbenes

The Chemistry of Alcohols and Thiols

The Chemistry of Ethers, Epoxides, Glycols, and Sulfides

Introduction to Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

Dienes and Aromaticity

The Chemistry of Benzene and Its Derivatives

The Chemistry of Aryl Halides, Vinylic Halides, and Phenols

The Chemistry of Aldehydes and Ketones

The Chemistry of Carboxylic Acids

The Chemistry of Carboxylic Acid Derivatives

The Chemistry of Enolate Ions, Enols, and Α,β-Unsaturated Carbonyl Compounds

The Chemistry of Amines

Carbohydrates

The Chemistry of Thioesters, Phosphate Esters, and Phosphate Anhydrides

The Chemistry of the Aromatic Heterocycles and Nucleic Acids

Amino Acids, Peptides, and Proteins

Pericyclic Reactions

Filters

The compound was synthesized from MnO₂ oxidation. Deduce the structure of the starting material.

Determine the major organic product for the reaction. The product should have a molecular formula of C₁₀H₁₃Br.

Consider these alcohols and explain whether oxidation with pyridinium chlorochromate (PCC) and MnO₂ would give the same product, different products or no reaction.