Solved: (a) Menthol, used to flavor various foods and tobacco, is the most stable

Each of the following chiral alcohols is shown in a different format. Draw a structural formula for the alkyl bromide formed as the major product from each alcohol on reaction with hydrogen bromide. Use the same format for the alkyl bromide as the original alcohol. Give the IUPAC name for each alkyl bromide including its stereochemistry according to the Cahn-Ingold-Prelog R,S system.

The reaction of 2,2-dimethyl-1-propanol \(\left[\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{OH}\right]\), also known by the common name neopentyl alcohol, with HBr is very slow and gives 2-bromo-2-methylbutane as the major product. Give a mechanistic explanation for these observations. Text Trancription: [(CH_3)_3 CCH_2 OH]

The reaction of 3-tert-butyl-3-pentanol with hydrochloric acid gave the products shown. Write appropriate equations explaining the formation of each.

Bromomethylcycloheptane has been prepared in 92% yield by the reaction shown. Write a stepwise mechanism and use curved arrows to show electron flow. The reaction was carried out in water, so use \(\mathrm{H}_{3} \mathrm{O}^{+}\)as the proton donor in your mechanism. Is the rate-determining step unimolecular \(\left(S_{N} 1\right)\) or bimolecular \(\left(S_{N} 2\right)\) ? Text Transcription: H_3O^+ (S_N 1) (S_N 2)

Although useful in agriculture as a soil fumigant, methyl bromide is an ozone-depleting chemical, and its production is being phased out. The industrial preparation of methyl bromide is from methanol, by reaction with hydrogen bromide. Write a mechanism for this reaction and classify it as \(S_{N} 1\) or \(S_{N} 2\). Text Transcription: S_N 1 S_N 2

Chapter 6 will describe elimination reactions and their mechanisms. In one example, heating tert-butyl bromide in ethanol gives the alkene 2-methylpropene by a two-step mechanism: A potential energy diagram for the reaction provides additional information to complement the mechanism expressed in the equations for the two elementary steps. The energy relationships in the diagram are not only useful in their own right, but also aid in understanding the structural changes occurring at the transition state. Hammond’s postulate tells us that if two states occur consecutively, the closer they are in energy, the more similar they are in structure. Ethanol is: A. a catalyst B. a reactive intermediate C. a Brønsted acid D. a Brønsted base

According to the potential energy diagram, the overall reaction is: A. endothermic B. exothermic

Chapter 6 will describe elimination reactions and their mechanisms. In one example, heating tert-butyl bromide in ethanol gives the alkene 2-methylpropene by a two-step mechanism: A potential energy diagram for the reaction provides additional information to complement the mechanism expressed in the equations for the two elementary steps. The energy relationships in the diagram are not only useful in their own right, but also aid in understanding the structural changes occurring at the transition state. Hammond’s postulate tells us that if two states occur consecutively, the closer they are in energy, the more similar they are in structure. Classify the elementary steps in the mechanism according to their molecularity. A. Step 1 is unimolecular; step 2 is bimolecular. B. Step 1 is bimolecular; step 2 is unimolecular. C. Both steps are unimolecular. D. Both steps are bimolecular.

Chapter 6 will describe elimination reactions and their mechanisms. In one example, heating tert-butyl bromide in ethanol gives the alkene 2-methylpropene by a two-step mechanism: A potential energy diagram for the reaction provides additional information to complement the mechanism expressed in the equations for the two elementary steps. The energy relationships in the diagram are not only useful in their own right, but also aid in understanding the structural changes occurring at the transition state. Hammond’s postulate tells us that if two states occur consecutively, the closer they are in energy, the more similar they are in structure. Classify states 2–4 in the potential energy diagram. A. 2, 3, and 4 are transition states B. 2, 3, and 4 are reactive intermediates C. 2 and 4 are transition states; 3 is a reactive intermediate D. 2 and 4 are reactive intermediates; 3 is a transition state

Chapter 6 will describe elimination reactions and their mechanisms. In one example, heating tert-butyl bromide in ethanol gives the alkene 2-methylpropene by a two-step mechanism: A potential energy diagram for the reaction provides additional information to complement the mechanism expressed in the equations for the two elementary steps. The energy relationships in the diagram are not only useful in their own right, but also aid in understanding the structural changes occurring at the transition state. Hammond’s postulate tells us that if two states occur consecutively, the closer they are in energy, the more similar they are in structure. According to the diagram, the activation energy of the slow step is given by the energy difference between states A. 1 and 2 B. 2 and 3 C. 3 and 4 D. 1 and 5

Chapter 6 will describe elimination reactions and their mechanisms. In one example, heating tert-butyl bromide in ethanol gives the alkene 2-methylpropene by a two-step mechanism: A potential energy diagram for the reaction provides additional information to complement the mechanism expressed in the equations for the two elementary steps. The energy relationships in the diagram are not only useful in their own right, but also aid in understanding the structural changes occurring at the transition state. Hammond’s postulate tells us that if two states occur consecutively, the closer they are in energy, the more similar they are in structure. What best describes the species at the rate-determining transition state?

Chapter 6 will describe elimination reactions and their mechanisms. In one example, heating tert-butyl bromide in ethanol gives the alkene 2-methylpropene by a two-step mechanism: A potential energy diagram for the reaction provides additional information to complement the mechanism expressed in the equations for the two elementary steps. The energy relationships in the diagram are not only useful in their own right, but also aid in understanding the structural changes occurring at the transition state. Hammond’s postulate tells us that if two states occur consecutively, the closer they are in energy, the more similar they are in structure. By applying Hammond’s postulate to the potential energy diagram for this reaction, we can say that: A. the structure of 2 is more carbocation-like than 4 B. the structure of 2 is less carbocation-like than 4 C. the structure of 2 resembles 1 more than it resembles 3 D. the structure of 4 resembles 5 more than it resembles 3

a) Write a structural formula for a sulfide having the molecular formula C3H8S. (b) What two thiols have the molecular formula C3H8S?

A footnote to Table 5.1 states “The example given is a primary amine (RNH2). Secondary amines have the general structure R2NH; tertiary amines are R3N.” Eight constitutionally isomeric amines have the molecular formula C4H11N. Write their structural formulas and classify each as a primary, secondary, or tertiary amine as appropriate.

Many compounds contain more than one functional group. Elenolic acid is obtained from olive oil and contains three carbonyl groups. Classify each type according to Table 5.1. Identify the most acidic proton in elenolic acid and use Table 1.8 to estimate its pKa.

Write structural formulas and give the functional class and substitutive names of all the isomeric alkyl chlorides that have the molecular formula C4H9Cl.

Write structural formulas, and give the functional class and substitutive names of all the isomeric alcohols that have the molecular formula C4H10O.

Classify the isomeric C4H10O alcohols as being primary, secondary, or tertiary.

Write structural formulas for all the isomers of (C3H8O). One of these is a gas at 25°C. Which one? Why?

Adapt Mechanism 5.1 so that it applies to the preparation of tert-butyl chloride using aqueous hydrochloric acid according to the following equation. \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{COH}+\mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{Cl}^{-} \longrightarrow\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCl}+2 \mathrm{H}_{2} \mathrm{O}\) Show each elementary step and write the structural formulas in a bond-line format showing curved arrows and all unshared electron pairs. Text Transcription: (CH_3)_3COH+H_3O^+ +Cl^- longrightarrow (CH_3)_3CCl+2H_2O

Assume the reaction follows an SN1 mechanism, and writes a chemical equation for the rate-determining step. Use curved arrows to show the flow of electrons.

Carbocations are key intermediates in petroleum refining. Of particular importance is one having the carbon skeleton shown. How many different C8H17+ carbocations have this carbon skeleton? Write a line formula for each and classify the carbocation as primary, secondary, or tertiary. The most stable of them corresponds to the intermediate in petroleum refining. Which one is it?

Which would you expect to be more stable: (CH3)3C+ or (CF3)3C+? Why?

For the general case of R = any alkyl group, how many bonded pairs of electrons are involved in stabilizing R3C+ by hyperconjugation? How many in R2CH+? In RCH2+?

Two stereoisomeric bromides are formed in the reaction of hydrogen bromide with the 4-methyl-2-hexanol stereoisomer shown. Write structural formulas showing their stereochemistry, identify the configuration of all chirality centers as R or S, and predict which stereoisomer is the major product.

For the reaction of a primary alcohol RCH2OH with thionyl chloride in pyridine, use curved arrows to show how the last intermediate can be transformed to RCH2Cl by reacting with chloride ion in a single step. Two additional compounds are formed. What are they?

Name each of the following compounds according to substitutive IUPAC nomenclature: (a) (CH3)2CH2H2CH2CH2Br (b) (CH3)2CHCH2CH2CH2OH (c) Cl3CCH2Br (e) CF3CH2OH

Write structural formulas for all the constitutionally isomeric alcohols of molecular formula C5H12O. Assign a substitutive and a functional class name to each one, and specify whether it is a primary, secondary, or tertiary alcohol.

Epichlorohydrin is the common name of an industrial chemical used as a component in epoxy cement. The molecular formula of epichlorohydrin is C3H5ClO. Epichlorohydrin has an epoxide functional group; it does not have a methyl group. Write a structural formula for epichlorohydrin.

(a) Complete the structure of the pain-relieving drug ibuprofen on the basis of the fact that ibuprofen is a carboxylic acid that has the molecular formula C13H18O2, X is an isobutyl group, and Y is a methyl group. (b) Mandelonitrile may be obtained from peach flowers. Derive its structure from the template in part (a) given that X is hydrogen, Y is the functional group that characterizes alcohols, and Z characterizes nitriles.

Some of the most important organic compounds in biochemistry are the \(\alpha\)-amino acids, represented by the general formula shown. Write structural formulas for the following \(\alpha\)-amino acids. (a) Alanine (R = methyl) (b) Valine (R = isopropyl) (c) Leucine (R = isobutyl) (d) Isoleucine (R = sec-butyl) (e) Serine (R = XCH2, where X is the functional group that characterizes alcohols) (f) Cysteine (R = XCH2, where X is the functional group that characterizes thiols) (g) Aspartic acid (R = XCH2, where X is the functional group that characterizes carboxylic acids) Text Transcription: alpha

The compound zoapatanol was isolated from the leaves of a Mexican plant. Classify each oxygen in zoapatanol according to the functional group to which it belongs. If an oxygen is part of an alcohol, classify the alcohol as primary, secondary, or tertiary.

Consult Table 5.1 and classify each nitrogen-containing functional group in the anesthetic lidocaine according to whether it is an amide, or a primary, secondary, or tertiary amine.

Uscharidin is a natural product present in milkweed. It has the structure shown. Locate all of the following in uscharidin: (a) Alcohol, aldehyde, ketone, and ester functional groups (b) Methylene groups (c) Primary carbons

Write a chemical equation for the reaction of 1-butanol with each of the following: (a) Sodium amide (NaNH2) (b) Hydrogen bromide, heat (c) Sodium bromide, sulfuric acid, heat (d) Phosphorus tribromide (e) Thionyl chloride (f) Methanesulfonyl chloride, pyridine

Each of the following reactions has been described in the chemical literature and involves an organic reactant somewhat more complex than those we have encountered so far. Nevertheless, on the basis of the topics covered in this chapter, you should be able to write the structure of the principal organic product of each reaction.

On reaction with hydrogen chloride, one of the trimethylcyclohexanols shown gives a single product, the other gives a mixture of two stereoisomers. Explain.

Which alcohol is converted to the corresponding chloride at the fastest rate on reaction with concentrated hydrochloric acid? Which one reacts at the slowest rate?

The compound shown was used as a building block in the synthesis of an HIV protease inhibitor. Write an equation for the preparation of this compound from a suitable alcohol and a reactant of your choice.

Alcohols in which the hydroxyl group occupies a “bridgehead” position such as bicyclo[2.2.1]heptan-1-ol are relatively unreactive toward hydrogen halides. Why?

Bromine is less electronegative than chlorine, yet methyl bromide and methyl chloride have very similar dipole moments. Why?

Write chemical equations for the reaction that takes place between each of the following pairs of reactants: (a) 2-Butanol and hydrogen bromide (b) 3-Ethyl-3-pentanol and hydrogen chloride (c) 1-Tetradecanol and hydrogen bromide

Sketch a potential energy diagram for the reaction of 1-heptanol with hydrogen bromide, paying careful attention to the positioning and structures of the intermediates and transition states.

Write a chemical equation describing the preparation of cis-4-tert-butylcyclohexyl methanesulfonate.

Write structural formulas for each of the following alcohols and alkyl halides: (a) Cyclobutanol (b) sec-Butyl alcohol (c) 3-Heptanol (d) trans-2-Chlorocyclopentanol (e) 2,6-Dichloro-4-methyl-4-octanol (f) trans-4-tert-Butylcyclohexanol (g) 1-Cyclopropylethanol (h) 2-Cyclopropylethanol

Each of the following is a functional class name developed according to the 1993 IUPAC recommendations. Alkyl group names of this type are derived by naming the longest continuous chain that includes the point of attachment, numbering in the direction so as to give the substituted carbon the lower number. The -e ending of the corresponding alkane is replaced by -yl, which is preceded by the number corresponding to the substituted carbon bracketed by hyphens. Write a structural formula for each alkyl halide. (a) 6-Methylheptan-3-yl chloride (b) 2,2-Dimethylpentan-3-yl bromide (c) 3,3-Dimethylcyclopentan-1-yl alcohol

A hydroxyl group is a somewhat “smaller” substituent on a six-membered ring than is a methyl group. That is, the preference of a hydroxyl group for the equatorial orientation is less pronounced than that of a methyl group. Given this information, write structural formulas for all the isomeric methylcyclohexanols, showing each one in its most stable conformation. Give the substitutive IUPAC name for each isomer.

(a) Menthol, used to flavor various foods and tobacco, is the most stable stereoisomer of 2-isopropyl-5-methylcyclohexanol. Draw its most stable conformation. Is the hydroxyl group cis or trans to the isopropyl group? To the methyl group? (b) Neomenthol is a stereoisomer of menthol. That is, it has the same constitution but differs in the arrangement of its atoms in space. Neomenthol is the second most stable stereoisomer of 2-isopropyl-5-methylcyclohexanol; it is less stable than menthol but more stable than any other stereoisomer. Write the structure of neomenthol in its most stable conformation.

Isoamyl acetate is the common name of the substance most responsible for the characteristic odor of bananas. Write a structural formula for isoamyl acetate, given the information that it is an ester in which the carbonyl group bears a methyl substituent and there is a 3-methylbutyl group attached to one of the oxygens.

n-Butyl mercaptan is the common name of a foul-smelling substance obtained from skunk spray. It is a thiol of the type RX, where R is an n-butyl group and X is the functional group that characterizes a thiol. Write a structural formula for this substance.

Select the compound in each of the following pairs that will be converted to the corresponding alkyl bromide more rapidly on being treated with hydrogen bromide. Explain the reason for your choice. (a) 1-Butanol or 2-butanol (b) 2-Methyl-1-butanol or 2-butanol (c) 2-Methyl-2-butanol or 2-butanol (d) 2-Methylbutane or 2-butanol (e) 1-Methylcyclopentanol or cyclohexanol (f) 1-Methylcyclopentanol or trans-2-methylcyclopentanol (g) 1-Cyclopentylethanol or 1-ethylcyclopentanol

(a) Assuming that the rate-determining elementary step in the reaction of trans-4- methylcyclohexanol with hydrogen bromide is unimolecular, write an equation for this step. Use curved arrows to show electron flow. (b) Two stereoisomers of 1-bromo-4-methylcyclohexane are formed when trans-4- methylcyclohexanol reacts with hydrogen bromide. Write a separate equation for the elementary step that gives each stereoisomer.