The following alkyl halide can be prepared by addition of

Classify each of the following reactions as an addition, elimination, substitution, or rearrangement: (a) \(\mathrm{CH}_{3} \mathrm{Br}+\mathrm{KOH} \rightarrow \mathrm{CH}_{3} \mathrm{OH}+\mathrm{KBr}\) (b) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Br} \rightarrow \mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}+\mathrm{HBr}\) (c) \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}+\mathrm{H}_{2} \rightarrow \mathrm{CH}_{3} \mathrm{CH}_{3}\) ________________ Equation Transcription: Text Transcription: CH_{3}Br+KOH rightarrow CH_{3}OH+KBr CH_{3}CH_{2}Br rightarrow H_{2}C=CH_{2}+HBr H_{2}C=CH_{2}+H_{2} rightarrow CH_{3} CH_{3}

Radical chlorination of alkanes is not generally useful because mixtures of products often result when more than one kind of \(\mathrm{C-H}\) bond is present in the substrate. Draw and name all monochloro substitution products \(\mathrm{C_6H_{13}Cl}\) you might obtain by reaction of 2-methylpentane with \(\mathrm{Cl_2}\). ________________ Equation Transcription: Text Transcription: C-H C_6H_{13}Cl Cl_2

Using curved fishhook arrows, propose a mechanism for the formation of the cyclopentane ring of prostaglandin \(\mathrm{H_2}\). ________________ Equation Transcription: Text Transcription: H_2 CO_2H CO_2H

Which of the following species is likely to behave as a nucleophile and which as an electrophile? (a) \(\mathrm{NO_2^+}\) (b) \(\mathrm{CN^-}\) (c) \(\mathrm{CH_3NH_2}\) (d) \(\mathrm{(CH_3)_3S^+}\) ________________ Equation Transcription: Text Transcription: NO_2^+ CN^- CH_3NH_2 (CH_3)_3S^+

Which of the following species are likely to be nucleophiles and which electrophiles? Which might be both? (a) \(\mathrm {CH_3Cl}\) (b) \(\mathrm {CH_3S^-}\) ________________ Equation Transcription: Text Transcription: CH_3Cl CH_3S^- CH_3 CH_3CH

An electrostatic potential map of boron trifluoride is shown. Is \(\mathrm {BF_3}\) likely to be a nucleophile or an electrophile? Draw a Lewis structure for \(\mathrm {BF_3}\), and explain your answer. ________________ Equation Transcription: Text Transcription: BF_3 BF_3 BF_3

What product would you expect from reaction of cyclohexene with HBr? With HCl?

Reaction of HBr with 2-methylpropene yields 2-bromo-2-methylpropane. What is the structure of the carbocation formed during the reaction? Show the mechanism of the reaction. ________________ Equation Transcription: Text Transcription: H_3C H_3C C=CH_2+HBr CH_3 CH_3-C-Br CH_3

It takes practice to use curved arrows properly in reaction mechanisms, but there are a few rules and a few common patterns you should look for that will help you become more proficient:

Add curved arrows to the following polar reaction to show the flow of electrons: ________________ Equation Transcription: Text Transcription: H_3C H_3C CH_3 Br^-

Add curved arrows to the following polar reactions to indicate the flow of electrons in each: ________________ Equation Transcription: Text Transcription: N^+ CH_3 CH_3 CH_3 H_3C OCH_3 OCH_3 H_3C

Predict the products of the following polar reaction, a step in the citric acid cycle for food metabolism, by interpreting the flow of electrons indicated by the curved arrows: ________________ Equation Transcription: Text Transcription: ^-O_2C CH_2 CO_2^- CO_2^- O:^+

Which reaction is more energetically favored, one with \(\Delta G^\circ=-44\ \mathrm {kJ/mol}\) or one with \(\Delta G^\circ=+44\ \mathrm {kJ/mol}\)? ________________ Equation Transcription: Text Transcription: Delta G^o=-44 kJ/mol Delta G^o=+44 kJ/mol

Which reaction is likely to be more exergonic, one with \(K_{\mathrm {eq}}=1000\) or one with \(K_{\mathrm {eq}}=0.001\)? ________________ Equation Transcription: Text Transcription: K_{eq}=1000 K_{eq}=0.001

Which reaction is faster, one with \(\Delta G^{\ddagger}=+45 \mathrm{~kJ} / \mathrm{mol}\) or one with \(\Delta G^{\ddagger}=+70 \mathrm{~kJ} / \mathrm{mol}\)? ________________ Equation Transcription: Text Transcription: Delta G^{ddagger}=+45 kJ/mol Delta G^{ddagger}=+70 kJ/mol

Sketch an energy diagram for a one-step reaction that is fast and highly exergonic.

Sketch an energy diagram for a two-step exergonic reaction whose second step has a higher-energy transition state than its first step. Show \(\Delta G^{\ddagger}\) and \(\Delta G^{\circ}\) for the overall reaction. ________________ Equation Transcription: Text Transcription: Delta G^ddagger Delta G^o

Sketch an energy diagram for a two-step reaction in which both steps are exergonic and in which the second step has a higher-energy transition state than the first. Label the parts of the diagram corresponding to reactant, product, intermediate, overall \(\Delta G^{\ddagger}\), and overall \(\Delta G^{\circ}\). ________________ Equation Transcription: Text Transcription: Delta G^ddagger Delta G^o

The following alkyl halide can be prepared by addition of HBr to two different alkenes. Draw the structures of both (reddish-brown = Br).

The following structure represents the carbocation intermediate formed in the addition reaction of HBr to two different alkenes. Draw the structures of both.

Electrostatic potential maps of (a) formaldehyde \(\left(\mathrm{CH}_{2} \mathrm{O}\right)\) and (b) methanethiol \(\left(\mathrm{CH}_{3} \mathrm{SH}\right)\) are shown. Is the formaldehyde carbon atom likely to be electrophilic or nucleophilic? What about the methanethiol sulfur atom? Explain. ________________ Equation Transcription: Text Transcription: (CH_2O) (CH_3SH)

Look at the following energy diagram: (a) Is \(\Delta G^\circ\) for the reaction positive or negative? Label it on the diagram. (b) How many steps are involved in the reaction? (c) How many transition states are there? Label them on the diagram. ________________ Equation Transcription: Text Transcription: Delta G^o

Look at the following energy diagram for an enzyme-catalyzed reaction: (a) How many steps are involved? (b) Which step is most exergonic? (c) Which step is slowest?

What is the difference between a transition state and an intermediate?

Draw an energy diagram for a one-step reaction with \(K_\mathrm{{eq}}<1\). Label the parts of the diagram corresponding to reactants, products, transition state, \(\Delta G^\circ\), and \(\Delta G^\ddagger\). Is \(\Delta G^\circ\) positive or negative? ________________ Equation Transcription: Text Transcription: K_{eq}<1 Delta G^o Delta G^ddagger Delta G^o

Draw an energy diagram for a two-step reaction with \(K_\mathrm{{eq}}>1\). Label the overall \(\Delta G^\circ\), transition states, and intermediate. Is \(\Delta G^\circ\) positive or negative? ________________ Equation Transcription: Text Transcription: K_{eq}>1 Delta G^o Delta G^o

Draw an energy diagram for a two-step exergonic reaction whose second step is faster than its first step.

Draw an energy diagram for a reaction with \(K_\mathrm{{eq}}=1\). What is the value of \(\Delta G^\circ\) in this reaction? ________________ Equation Transcription: Text Transcription: K_{eq}=1 Delta G^o

The addition of water to ethylene to yield ethanol has the following thermodynamic parameters: \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}+\mathrm{H}_{2} \mathrm{O} \rightleftarrows \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\ \ \left\{\begin{array}{l} \Delta \mathrm{H}^{\circ}=-44 \mathrm{~kJ} / \mathrm{mol} \\ \Delta S^{\circ}=-0.12 \mathrm{~kJ} /(\mathrm{K} \cdot \mathrm{mol}) \\ K_{\mathrm{eq}}=24 \end{array}\right. \) (a) Is the reaction exothermic or endothermic? (b) Is the reaction favorable (spontaneous) or unfavorable (nonspontaneous) at room temperature (298 K)? ________________ Equation Transcription: ? Text Transcription: H_2C=CH_2+H_2O{}CH_3CH_2OH Delta H^o=-44 kJ/mol Delta S^o=-0.12 kJ/(K cdot mol) K_eq=24

When isopropylidenecyclohexane is treated with strong acid at room temperature, isomerization occurs by the mechanism shown below to yield 1-isopropylcyclohexene: At equilibrium, the product mixture contains about 30% isopropylidenecyclohexane and about 70% 1-isopropylcyclohexene. (a) What is an approximate value of \(K_{\mathrm {eq}}\) for the reaction? (b) Since the reaction occurs slowly at room temperature, what is its approximate \(\Delta G^\ddagger\)? (c) Draw an energy diagram for the reaction. ________________ Equation Transcription: Text Transcription: CH_3 CH_3 H^+ CH_3 CH_3 CH_3 CH_3 H^+ K_{eq} Delta G^ddagger

Add curved arrows to the mechanism shown in Problem 6-25 to indicate the electron movement in each step.

Draw the electron-pushing mechanism for each radical reaction below. Identify each step as initiation, propagation, or termination. ________________ Equation Transcription: Text Transcription: Cl_2 Br_2 CH_3Cl+Br_2

Draw the complete mechanism for each polar reaction below.

Use curved arrows to show the flow of electrons, and draw the carbon radical that is formed when the halogen radicals below add to the corresponding alkenes. ________________ Equation Transcription: Text Transcription: Cl{cdot} Br{cdot} Cl{cdot}

Identify the functional groups in the following molecules, and show the polarity of each: ________________ Equation Transcription: Text Transcription: CH_3CH_2C{equiv}N OCH_3 CH_3CCH_2COCH_3 NH_2

Identify the following reactions as additions, eliminations, substitutions, or rearrangements: (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Br}+\mathrm{NaCN} \longrightarrow \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CN}(+\mathrm{NaBr})\) ________________ Equation Transcription: Text Transcription: CH_3CH_2Br+NaCNCH_3CH_2CN(+NaBr) (+H_2O) O_2N-NO_2 NO_2 (+HNO_2)

Identify the likely electrophilic and nucleophilic sites in each of the following molecules: ________________ Equation Transcription: Text Transcription: CH_3 CH_3 CH_3 NHCH_3

For each reaction below identify the electrophile and the nucleophile. ________________ Equation Transcription: Text Transcription: N_3+CH_3ClCH_3N_3+Cl NO_2 NO_2 CH_3 H_3C

Add curved arrows to the following polar reactions to indicate the flow of electrons in each: ________________ Equation Transcription: Text Transcription: D-Cl Cl^- H-Cl CH_3 H-Cl CH_3 Cl^- CH_3

Follow the flow of electrons indicated by the curved arrows in each of the following polar reactions, and predict the products that result: ________________ Equation Transcription: Text Transcription: H_3C H_3C OCH_3 CH_3 H_3C CH_3

When a mixture of methane and chlorine is irradiated, reaction commences immediately. When irradiation is stopped, the reaction gradually slows down but does not stop immediately. Explain

Radical chlorination of pentane is a poor way to prepare 1-chloropentane, but radical chlorination of neopentane, \(\left(\mathrm{CH}_{3}\right)_{4} \mathrm{C}\), is a good way to prepare neopentyl chloride, \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{Cl}\). Explain. ________________ Equation Transcription: Text Transcription: (CH_3)_4C (CH_3)_3CCH_2Cl

Despite the limitations of radical chlorination of alkanes, the reaction is still useful for synthesizing certain halogenated compounds. For which of the following compounds does radical chlorination give a single monochloro product? (a) \(\mathrm {CH_3CH_3}\) (b) \(\mathrm {CH_3CH_2CH_3}\) (c) (d) (e) \(\mathrm {CH_3C \equiv CCH_3}\) (f) Equation Transcription: Text Transcription: CH_3CH_3 CH_3CH_2CH_3 CH_3 CH_3CCH_2CH_3 CH_3 CH_3{equiv}CCH_3 H_3C H_3C CH_3 CH_3 CH_3 CH_3

Draw all of the different monochlorinated products one would obtain by the radical chlorination of these compounds. (Do not consider the stereochemistry of the products in your answer.)

Answer question 6-39 taking all stereoisomers into account.

For each alkene below, use curved arrows to show how it would react with a proton. Draw the carbocation that would form in each case.

2-Chloro-2-methylpropane reacts with water in three steps to yield 2-methyl-2-propanol. The first step is slower than the second, which in turn is much slower than the third. The reaction takes place slowly at room temperature, and the equilibrium constant is approximately 1. (a) Give approximate values for \(\Delta G^{\ddagger}\) and \(\Delta G^{\circ}\) that are consistent with the above information. (b) Draw an energy diagram for the reaction, labeling all points of interest and making sure that the relative energy levels on the diagram are consistent with the information given. ________________ Equation Transcription: Text Transcription: CH_3 H_3C-C-Cl CH_3 H_3C-C^+ CH_3 CH_3 C^+ H_2O H_3C-C-O^+ CH_3 CH_3 H_2O CH_3 H_3C-O-H+H_3O^++Cl^- CH_3 Delta G^ddagger Delta G^o

Add curved arrows to the mechanism shown in Problem 6-42 to indicate the electron movement in each step.

The reaction of hydroxide ion with chloromethane to yield methanol and chloride ion is an example of a general reaction type called a nucleophilic substitution reaction: \(\mathrm{HO}^{-}+\mathrm{CH}_{3} \mathrm{Cl} \rightleftarrows \mathrm{CH}_{3} \mathrm{OH}+\mathrm{Cl}^{-}\) The value of \(\Delta H^\circ\) for the reaction is \(-75\) kJ/mol, and the value of \(\Delta S^\circ\) is \(\mathrm{+54\ J/(K \cdot mol)}\). What is the value of \(\Delta G^\circ\) (in kJ/mol) at 298 K? Is the reaction exothermic or endothermic? Is it exergonic or endergonic? ________________ Equation Transcription: ? Text Transcription: HO^-+CH_3Cl ? CH3OH+Cl^- Delta H^o Delta S^o +54 J/(K cdot mol) Delta G^o

Methoxide ion \(\mathrm{\left(CH_3O^-\right)}\) reacts with bromoethane in a single step according to the following equation: Identify the bonds broken and formed, and draw curved arrows to represent the flow of electrons during the reaction. ________________ Equation Transcription: Text Transcription: (CH_3O^-) CH_3OH

Ammonia reacts with acetyl chloride \(\mathrm{\left(CH_3COCl\right)}\) to give acetamide \(\mathrm{\left(CH_3CONH_2\right)}\). Identify the bonds broken and formed in each step of the reaction, and draw curved arrows to represent the flow of electrons in each step. ________________ Equation Transcription: Text Transcription: (CH_3COCl) (CH_3CONH_2) H_3C NH_3 H_3C NH_3^+ H_3C NH_3^+ NH_3 H_3C NH_2 NH_4^+Cl^-

The naturally occurring molecule \(\alpha\)-terpineol is biosynthesized by a route that includes the following step: (a) Propose a likely structure for the isomeric carbocation intermediate. (b) Show the mechanism of each step in the biosynthetic pathway, using curved arrows to indicate electron low. ________________ Equation Transcription: Text Transcription: H_3C CH_3 H_2C CH_3 H_2O H_3C H_3C CH_3

Predict the product(s) of each of the following biological reactions by interpreting the low of electrons as indicated by the curved arrows: ________________ Equation Transcription: Text Transcription: H_3C CH_3 H_3C OPO_3^2- ^{2-}O_3POCH_2 H_3C CO_2^- CH_3

Reaction of 2-methylpropene with HBr might, in principle, lead to a mixture of two alkyl bromide addition products. Name them, and draw their structures.

Draw the structures of the two carbocation intermediates that might form during the reaction of 2-methylpropene with HBr (Problem 6-49). We’ll see in the next chapter that the stability of carbocations depends on the number of alkyl substituents attached to the positively charged carbon—the more alkyl substituents there are, the more stable the cation. Which of the two carbocation intermediates you drew is more stable?

What is the relationship between isomers A and B? (a) Diastereomers (b) Enantiomers (c) Meso (d) Racemic (e) They are constitutional isomers.

What would a 50:50 mixture of these two isomers be called? (a) Diastereomers (b) Enantiomers (c) Meso forms (d) Racemic (e) Constitutional isomers

The chiral centers in isomers A and B are (a) R and S respectively (b) Prochiral (c) S and R respectively (d) Homotopic

Further research by medicinal chemists created a host of thalidomide analogues, among them is the drug pomalidomide. This drug is found to have an efficacy 2000 times that of thalidomide for the treatment of multiple myeloma. Based on the figure shown, identify the functional groups present in pomalidomide. (a) (a) phenyl, (b) amine, (c) amide. (b) (a) phenyl, (b) amide, (c) amine. (c) (a) phenol, (b) amine, (c) amide. (d) (a) phenol, (b) amide, (c) amine. ________________ Equation Transcription: Text Transcription: NH_2

Interconversion of the two forms of thalidomide takes place in an aqueous medium. This mechanism involves a type of rearrangement called epimerization (isomerization at a single chiral center). In this epimerization the water molecules are acting as (a) Brønsted bases (b) Brønsted acids (c) Nucleophiles (d) Electrophiles ________________ Equation Transcription: Text Transcription: H-OH_2 H_2O H=OH_2 H_2O