Exam 2: Chapter 10 - Structure and Synthesis of Alcohols

Question 1

What is the first step in naming alcohols in nomenclature?

Answer 1

Find the longest continuous chain of carbons that has the -OH group attached.

Question 2

How do you number the longest carbon chain in alcohol nomenclature?

Answer 2

Number the longest chain from the end closest to the -OH group.

Question 3

What takes priority over all other groups in alcohol nomenclature?

Answer 3

-OH group takes priority over all other groups.

Question 4

What is the naming convention for cyclic alcohols?

Answer 4

-OH is assumed to be on carbon 1.

Question 5

What is the structural formula for 7-chloroheptan-3-ol?

Answer 5

C7H15ClO

Question 6

What are the physical properties of alcohols influenced by?

Answer 6

The presence of the hydroxyl (-OH) group and the alkyl chain.

Question 7

Why do alcohols have higher boiling points than alkanes with similar molecular weights?

Answer 7

Due to hydrogen bonding between the -OH groups of alcohol molecules.

Question 8

What effect does increasing alkyl chain length have on boiling points of alcohols?

Answer 8

Boiling point tends to increase due to increased surface area and stronger London Dispersion Forces.

Question 9

How does branching in the alkyl chain affect boiling points?

Answer 9

Increased branching can lead to a decrease in boiling point due to reduced surface area.

Question 10

What influences the solubility of alcohols in water?

Answer 10

The balance between the hydrophilic -OH group and the hydrophobic alkyl chain.

Question 11

How does the length of the nonpolar alkyl chain affect an alcohol’s solubility in water?

Answer 11

Longer hydrophobic alkyl chains decrease solubility in water.

Question 12

What effect does branching have on the solubility of alcohols?

Answer 12

More branched alcohols can be more easily surrounded by water molecules, increasing solubility.

Question 13

How do multiple -OH groups affect the solubility of alcohols?

Answer 13

Alcohols with multiple -OH groups exhibit higher water solubility due to increased hydrogen bonding opportunities.

Question 14

What structural features influence the acidity of alcohols?

Answer 14

Inductive effects of alkyl groups, hybridization of the carbon atom, lack of resonance stabilization, and presence of other substituents.

Question 15

How do alkyl groups affect the acidity of alcohols?

Answer 15

Alkyl groups are electron-donating and increase electron density around the oxygen, making the conjugate base less stable and the alcohol less acidic.

Question 16

What is the hybridization of the carbon atom that the -OH group is bonded to in alcohols?

Answer 16

sp3 hybridized.

Question 17

Why are alcohols less acidic than phenols?

Answer 17

Alcohols lack resonance stabilization in their conjugate bases compared to phenols.

Question 18

What effect do electron-withdrawing groups have on the acidity of alcohols?

Answer 18

They can stabilize the negative charge in the alkoxide ion, thus increasing the acidity of the alcohol.

Question 19

What is a key method for synthesizing alcohols from alkyl halides?

Answer 19

SN2 reactions.

Question 20

What is one method to synthesize alcohols from alkenes?

Answer 20

Acid-catalyzed hydration.

Question 21

What do Grignard reagents react with to form alcohols?

Answer 21

Carbonyl compounds.

Question 22

What is the result of reducing aldehydes with NaBH₄ or LiAlH₄?

Answer 22

Primary alcohols.

Question 23

What do ketones yield when reduced by NaBH₄ or LiAlH₄?

Answer 23

Secondary alcohols.

Question 24

What is the role of catalytic hydrogenation in the synthesis of alcohols?

Answer 24

Addition of H₂ over a metal catalyst to form alcohols from carbonyl compounds.

Question 25

What is the first step in designing a synthesis for an alcohol?

Answer 25

Analyze the starting material and the target product.

Question 26

Why is it important to identify functional group transformations in synthesis?

Answer 26

To determine the types of reactions needed to convert the starting material into the product.

Question 27

What should be considered when planning a step-wise synthesis?

Answer 27

The order of transformations and the specific reactions needed.

Question 28

What must be included in the synthesis instructions?

Answer 28

List all reagents and solvents used in each step.

Question 29

What potential issues should be considered during synthesis?

Answer 29

Potential side reactions and limitations.

Question 30

What is the importance of regioselectivity in reactions?

Answer 30

Regioselectivity determines whether Markovnikov or anti-Markovnikov addition occurs

Question 31

What does stereochemistry refer to in chemical reactions?

Answer 31

Stereochemistry refers to the spatial arrangement of atoms in molecules, affecting syn vs. anti addition

Question 32

List three methods for adding water to alkenes

Answer 32

* Catalyzed hydration * Oxymercuration-demercuration * Hydroboration-oxidation

Question 33

What is the role of Grignard reagents in synthesis?

Answer 33

Grignard reagents act as strong nucleophiles in reactions with carbonyl compounds

Question 34

Fill in the blank: Grignard reagents cannot be used in the presence of _______ protons.

Answer 34

acidic

Question 35

What should you do after designing a synthesis?

Answer 35

Double-check each step to ensure it produces the desired intermediate or product

Question 36

What is retrosynthesis?

Answer 36

Retrosynthesis is the process of working backward from a product to identify suitable starting materials

Question 37

How do you identify the type of alcohol in retrosynthesis?

Answer 37

Examine the connectivity of the carbon atom bearing the hydroxyl (-OH) group

Question 38

What do you disconnect to identify potential precursors for alcohol synthesis?

Answer 38

Disconnect the carbon bearing the -OH group from its attached alkyl or aryl groups

Question 39

What must a disconnection lead to for primary alcohols?

Answer 39

One disconnection must lead to formaldehyde (H₂C=O)

Question 40

What carbonyl compound must be produced for secondary alcohols?

Answer 40

One disconnection must lead to an aldehyde (R'CHO)

Question 41

What is a key consideration for tertiary alcohols in retrosynthesis?

Answer 41

Disconnection can lead to a ketone (R'R''C=O) or can be formed from esters or acid chlorides

Question 42

What is important when specifying reagents and solvents in synthesis?

Answer 42

Clearly list the alkyl or aryl halide, the metal, and the solvent used

Question 43

What should be shown if multiple steps are involved in a synthesis?

Answer 43

Show the structure of the alkoxide intermediate formed after the addition of the organometallic reagent

Question 44

What should you aim for in your proposed synthesis pathway?

Answer 44

One efficient pathway using readily available starting materials

Question 45

What is a critical step in illustrating chemical reaction mechanisms?

Answer 45

Identify the type of reaction being presented

Question 46

What are the two types of nucleophilic substitution reactions?

Answer 46

* SN1 * SN2

Question 47

What is a characteristic of SN2 reactions?

Answer 47

Concerted reaction with backside attack and inversion of configuration

Question 48

What type of reagent is used in hydride reductions?

Answer 48

Hydride reagents like NaBH₄ and LiAlH₄

Question 49

What is the outcome of acid-catalyzed dehydration of alcohols?

Answer 49

Formation of alkenes through carbocation formation and loss of water

Question 50

What should be included when drawing mechanisms?

Answer 50

All intermediates, lone pairs, formal charges, and electron flow with curved arrows

Question 51

True or False: Stereochemistry is irrelevant in chemical reaction mechanisms.

Answer 51

False

Question 52

What must you confirm when naming the product of a mechanism?

Answer 52

Ensure familiarity with IUPAC nomenclature for organic compounds

Question 53

Show the complete mechanism for the reaction of 3-butenylmagnesiumchloride with methyl benzoate. What is the first step?

Answer 53

React 1 mole of CH₂=CH₂CH₂CH₂-MgCl with the first reactant to remove MgCl

Question 54

What is the final step in the mechanism involving 3-butenylmagnesiumchloride?

Answer 54

React the product with H₃O⁺ to remove a lone pair from oxygen and make it OH