Compound A has the formula C8H8. It reacts rapidly with

One problem with elimination reactions is that mixtures of products are often formed. For example, treatment of 2-bromo-2-methylbutane with KOH in ethanol yields a mixture of two alkene products. What are their likely structures?

How many alkene products, including E,Z isomers, might be obtained by dehydration of 3-methyl-3-hexanol with aqueous sulfuric acid? ________________ Equation Transcription: Text Transcription: CH_3CH_2CH_2CCH_2CH_3 CH_3 H_2SO_4

What product would you expect to obtain from addition of \(\mathrm {Cl_2}\) to 1,2-dimethylcyclohexene? Show the stereochemistry of the product. ________________ Equation Transcription: Text Transcription: Cl_2

Addition of HCl to 1,2-dimethylcyclohexene yields a mixture of two products. Show the stereochemistry of each, and explain why a mixture is formed.

What product would you expect from the reaction of cyclopentene with NBS and water? Show the stereochemistry.

When an unsymmetrical alkene such as propene is treated with N-bromosuccinimide in aqueous dimethyl sulfoxide, the major product has the bromine atom bonded to the less highly substituted carbon atom. Is this Markovnikov or non-Markovnikov orientation? Explain. ________________ Equation Transcription: Text Transcription: CH_3CH=CH_2 Br_2,H_2O OH CH_3CHCH_2Br

What products would you expect from oxymercuration–demercuration of the following alkenes? (a) \(\mathrm {CH_3CH_2CH_2CH=CH_2}\) (b) ________________ Equation Transcription: Text Transcription: CH_3CH_2CH_2CH=CH_2 CH_3 CH_3C=CHCH_2CH_3

From what alkenes might the following alcohols have been prepared? ________________ Equation Transcription: Text Transcription: CH_3CCH_2CH_2CH_2CH_3 CH_3

What products would you obtain from reaction of 2-methyl-2-pentene with: (a) \(\mathrm{BH_3}\), followed by \(\mathrm{H_2O_2, OH^-}\) (b) \(\mathrm{Hg(OAc)_2}\), followed by \(\mathrm{NaBH_4}\) ________________ Equation Transcription: Text Transcription: BH_3 H_2O_2, OH^- Hg(OAc)_2 NaBH_4

How might you prepare the following alcohol? ________________ Equation Transcription: Text Transcription: CH_3 CH_3CH_2CHCHCH_2CH_3

Show the structures of the products you would obtain by hydroboration–oxidation of the following alkenes: ________________ Equation Transcription: Text Transcription: CH_3 CH_3C=CHCH_2CH_3 CH_3

What alkenes might be used to prepare the following alcohols by hydroboration–oxidation? ________________ Equation Transcription: Text Transcription: CH_3 CH_3CHCH_2CH_2OH H_3C CH_3CHCHCH_3 CH_2OH

The following cycloalkene gives a mixture of two alcohols on hydroboration followed by oxidation. Draw the structures of both, and explain the result.

What product would you obtain from catalytic hydrogenation of the following alkenes? ________________ Equation Transcription: Text Transcription: CH_3 CH_3C=CHCH_2CH_3 CH_3 CH_3 H_3C CH_3 CH_3 CH_3 CH_3 CH_3

What product would you expect from reaction of cis-2-butene with meta-chloroperoxybenzoic acid? Show the stereochemistry.

Starting with an alkene, how would you prepare each of the following compounds? ________________ Equation Transcription: Text Transcription: CH CH_3 CH_3CH_2CHCCH_3 CH_3 HOCH_2CHCHCH_2OH

What alkene would yield a mixture of cyclopentanone and propanal on treatment with ozone followed by reduction with zinc? ________________ Equation Transcription: Text Transcription: O_3 CH_3CH_2CH

What products would you expect from reaction of 1-methylcyclohexene with the following reagents? (a) Aqueous acidic \(\mathrm{KMnO_4}\) (b) \(O_3\), followed by Zn, \(\mathrm{CH_3CO_2H}\) ________________ Equation Transcription: Text Transcription: KMnO_4 O_3 CH_3CO_2H

Propose structures for alkenes that yield the following products on reaction with ozone followed by treatment with Zn: (a) \(\mathrm{(CH_3)_2C=O+H_2C=O}\) (b) 2 equiv \(\mathrm{CH_3CH_2CH=O}\) ________________ Equation Transcription: Text Transcription: (CH_3)_2C=O+H_2C=O CH_3CH_2CH=O

What products would you expect from the following reactions? ________________ Equation Transcription: Text Transcription: CH_2 CHCl_3 CH_3 CH_3CHCH_2CH=CHCH_3+CH_2I_2

Show the structure of poly(vinyl chloride), a polymer made from \(\mathrm{H_2C=CHCl}\), by drawing several repeating units. ________________ Equation Transcription: Text Transcription: H_2C=CHCl

Show the monomer units you would use to prepare the following polymers: ________________ Equation Transcription: Text Transcription: OCH_3 OCH_3 OCH_3 CH_2-CH-CH_2-CH-CH_2-CH

One of the chain-termination steps that sometimes occurs to interrupt polymerization is the following reaction between two radicals. Propose a mechanism for the reaction, using fishhook arrows to indicate electron flow. ________________ Equation Transcription: Text Transcription: CH_2CH_2 CH_2CH_3 CH=CH_2

What products are formed from acid-catalyzed hydration of racemic \((\pm)\)-4-methyl-1-hexene? What can you say about the relative amounts of the products? Is the product mixture optically active? ________________ Equation Transcription: Text Transcription: +/-

What products are formed from hydration of 4-methylcyclopentene? What can you say about the relative amounts of the products?

Name the following alkenes, and predict the products of their reaction with (1) meta-chloroperoxybenzoic acid, (2) \(\mathrm{KMnO_4}\) in aqueous acid, and (3) \(\mathrm{O_3}\), followed by Zn in acetic acid: Equation Transcription: Text Transcription: KMnO_4 O_3

Draw the structures of alkenes that would yield the following alcohols on hydration (red = O). Tell in each case whether you would use hydroboration–oxidation or oxymercuration–demercuration.

The following alkene undergoes hydroboration–oxidation to yield a single product rather than a mixture. Explain the result, and draw the product showing its stereochemistry.

From what alkene was the following 1,2-diol made, and what method was used, epoxide hydrolysis or \(\mathrm{OsO_4}\)? ________________ Equation Transcription: Text Transcription: OsO_4

Predict the products for the following reactions, showing the complete mechanism and appropriate stereochemistry: ________________ Equation Transcription: Text Transcription: Br_2 Cl_2 Cl_2

Predict the products for the reactions in Problem 8-26 if each were run in DMSO with water. Show the complete mechanism including appropriate regiochemistry and stereochemistry.

Draw the structures of the organoboranes formed when borane reacts with each alkene below, including the regiochemistry and stereochemistry as appropriate. Propose a mechanism for each reaction.

m-CPBA is not the only peroxyacid capable of epoxide formation. For each reaction below, predict the products and show the mechanism. ________________ Equation Transcription: Text Transcription: CF_3CO_3H CO_3H

Provide the mechanism and products for the acid-catalyzed epoxide opening reactions below, including appropriate stereochemistry. Equation Transcription: Text Transcription: H_3O^+ H_3C CH_3 H_3O^+ H_3C H_3O^+

Propose a curved-arrow mechanism to show how ozone \(\mathrm{(O_3)}\) reacts with a carbon–carbon double bond to form a molozonide, the first intermediate in ozonolysis. ________________ Equation Transcription: Text Transcription: (O_3)

Which of the reactions below would result in a product mixture that would rotate plane-polarized light? ________________ Equation Transcription: Text Transcription: CH_2 CH_3 H_2 H_3C CH_3 H_3O^+ H_3C O_3 H_3O^+

Reaction of 2-methylpropene with \(\mathrm{CH_3OH}\) in the presence of \(\mathrm{H_2SO_4}\) catalyst yields methyl tert-butyl ether, \(\mathrm{CH_3OC(CH_3)_3}\), by a mechanism analogous to that of acid-catalyzed alkene hydration. Write the mechanism, using curved arrows for each step. ________________ Equation Transcription: Text Transcription: CH_3OH H_2SO_4 CH_3OC(CH_3)_3

Iodine azide, \(\mathrm{IN_3}\), adds to alkenes by an electrophilic mechanism similar to that of bromine. If a monosubstituted alkene such as 1-butene is used, only one product results: (a) Add lone-pair electrons to the structure shown for \(\mathrm{IN_3}\), and draw a second resonance form for the molecule. (b) Calculate formal charges for the atoms in both resonance structures you drew for \(\mathrm{IN_3}\) in part (a). (c) In light of the result observed when IN3 adds to 1-butene, what is the polarity of the \(\mathrm{I-IN_3}\) bond? Propose a mechanism for the reaction using curved arrows to show the electron flow in each step. ________________ Equation Transcription: Text Transcription: IN_3 CH_3CH_2CH=CH_2+I-N=N=N CH_3CH_2CHCH_2I IN_3 IN_3 I-IN_3

10-Bromo-\(\alpha\)-chamigrene, a compound isolated from marine algae, is thought to be biosynthesized from \(\gamma\)-bisabolene by the following route: Draw the structures of the intermediate bromonium and cyclic carbocation, and propose mechanisms for all three steps. ________________ Equation Transcription: Text Transcription: alpha gamma gamma Br^+ -H^+ alpha

Isolated from marine algae, prelaureatin is thought to be biosynthesized from laurediol by the following route. Propose a mechanism. ________________ Equation Transcription: Text Transcription: Br^+

Dichlorocarbene can be generated by heating sodium trichloroacetate. Propose a mechanism for the reaction, and use curved arrows to indicate the movement of electrons in each step. What relationship does your mechanism bear to the base-induced elimination of HCl from chloroform? ________________ Equation Transcription: Text Transcription: O^- Na^+ 70^{o}c C:+CO_2+Nacl

Reaction of cyclohexene with mercury(II) acetate in \(\mathrm {CH_3OH}\) rather than \(\mathrm {H_2O}\), followed by treatment with \(\mathrm {NaBH_4}\), yields cyclohexyl methyl ether rather than cyclohexanol. Suggest a mechanism. ________________ Equation Transcription: Text Transcription: CH_3OH H_2O NaBH_4 Hg(OAc)_2, CH_3OH NaBH_4 OCH_3

Use your general knowledge of alkene chemistry to suggest a mechanism for the following reaction. ________________ Equation Transcription: Text Transcription: CO_2CH_3 Hg(OAc)_2 CO_2CH_3 AcO-Hg

Treatment of 4-penten-1-ol with aqueous \(\mathrm{Br_2}\) yields a cyclic bromo ether rather than the expected bromohydrin. Suggest a mechanism, using curved arrows to show electron movement. ________________ Equation Transcription: Text Transcription: Br_2 H_2C=CHCH_2CH_2CH_2OH Br_2,H2O CH_2Br

Hydroboration of 2-methyl-2-pentene at \(\mathrm{25\ ^\circ C}\), followed by oxidation with alkaline \(\mathrm {H_2O_2}\), yields 2-methyl-3-pentanol, but hydroboration at \(\mathrm{160\ ^\circ C}\) followed by oxidation yields 4-methyl-1-pentanol. Suggest a mechanism. ________________ Equation Transcription: Text Transcription: 25 ^o C H_2O_2 160 ^oC CH_3 CH_3C=CHCH_2CH_3 BH_3,THF,25 ^o C H_2O_2,OH^- H_3C CH_3CHCHCH_2CH_3 BH_3,THF, 160 ^o C H_2O_2,OH^- CH_3 CH_3CHCH_2CH_2CH_2OH

Predict the products of the following reactions (the aromatic ring is unreactive in all cases). Indicate regiochemistry when relevant. ________________ Equation Transcription: Text Transcription: H_2/Pd Br_2 OsO_4 Cl_2,H_2O CH_2I_2,Zn/cu

Suggest structures for alkenes that give the following reaction products. There may be more than one answer for some cases. ________________ Equation Transcription: Text Transcription: H_2/Pd CH_3 CH_3CHCH_2CH_2CH2CH_3 Br_2 CH_3 CH_2CHCHCH_2CHCH_3 H_2/Pd CH_3 CH_3 CH_3CHCHCH_2CH_2CH_2CH_3 CH_3 Hg(OAc)_2,H_2O NaBH_4 CH_3CH_2CH_2CHCH_3 CH_2I_2,Zn/Cu

Predict the products of the following reactions, showing both regiochemistry and stereochemistry where appropriate: ________________ Equation Transcription: Text Transcription: CH_3 O_3 Zn,H_3O^+ KMnO_4 H_3O^+ CH_3 BH_3 H_2O_2,^-OH CH_3 Hg(OAc)_2,H_2O NaBH_4

Which reaction would you expect to be faster, addition of HBr to cyclohexene or to 1-methylcyclohexene? Explain.

What product will result from hydroboration–oxidation of 1-methylcyclo pentene with deuterated borane, \(\mathrm {BD_3}\)? Show both the stereochemistry (spatial arrangement) and the regiochemistry (orientation) of the product. Equation Transcription: Text Transcription: BD_3

The cis and trans isomers of 2-butene give different cyclopropane products in the Simmons–Smith reaction. Show the structures of both, and explain the difference. Equation Transcription: Text Transcription: cis-CH_3CH=CHCH_3 CH_2I,ZN(Cu) trans-CH_3CH=CHCH_3 CH_2I,ZN(Cu)

Predict the products of the following reactions. Don’t worry about the size of the molecule; concentrate on the functional groups. ________________ Equation Transcription: Text Transcription: CH_3 CH_3 Br_2 OSO_4 NaHSO_3 BH_3,THF H_2O_2^,-OH CH_2I_2,Zn(Cu)

Addition of HCl to 1-methoxycyclohexene yields 1-chloro-1-methoxycyclohexane as a sole product. Use resonance structures of the carbocation intermediate to explain why none of the alternate regioisomer is formed. Equation Transcription: Text Transcription: OCH_3 OCH_3

How would you carry out the following transformations? Tell what reagents you would use in each case. Equation Transcription: Text Transcription: CH_3 CH_3 CH_3CH=CHCHCH_3 CH_3 CH_3CH CH_3CHCH H_3C CH_3 CH_3C=CH_2 CH_3 CH_3CHCH_2OH

Draw the structure of an alkene that yields only acetone, \(\mathrm {(CH_3)=O}\), on ozonolysis followed by treatment with \(\mathrm {Zn}\). Equation Transcription: Text Transcription: (CH_3)=O Zn

Show the structures of alkenes that give the following products on oxidative cleavage with \(\mathrm {KMnO_4}\) in acidic solution: Equation Transcription: Text Transcription: KMnO_4 CH_3CH_2CO_2H+CO_2 (CH_3)_2C=O+CH_3CH_2CH_2CO_2H (CH_3)_2C=O CH_3CH_2CCH_2CH_2CH_2CH_2CO_2H

In planning the synthesis of one compound from another, it’s just as important to know what not to do as to know what to do. The following reactions all have serious drawbacks to them. Explain the potential problems of each. Equation Transcription: Text Transcription: CH_3 CH_3C=CHCH_3 H_3C CH_3CHCHCH_3 OsO_4 NaHSO_3 O_3 CH_3 BH_3 H_2O_2,-OH CH_3

Which of the following alcohols could not be made selectively by hydroboration–oxidation of an alkene? Explain. Equation Transcription: Text Transcription: CH_3CH_2CH_2CHCH_3 (CH_3)_2CHC(CH_3)_2 CH_3 CH_3

Plexiglas, a clear plastic used to make many molded articles, is made by polymerization of methyl methacrylate. Draw a representative segment of Plexiglas. ________________ Equation Transcription: Text Transcription: H_2C CH_3 OCH_3

Poly(vinyl pyrrolidone), prepared from N-vinylpyrrolidone, is used both in cosmetics and as a synthetic substitute for blood. Draw a representative segment of the polymer. Equation Transcription: Text Transcription: N-CH=CH_2

When a single alkene monomer, such as ethylene, is polymerized, the product is a homopolymer. If a mixture of two alkene monomers is polymerized, however, a copolymer often results. The following structure represents a segment of a copolymer called Saran. What two monomers were copolymerized to make Saran?

Compound A has the formula \(\mathrm{C_{10}H_{16}}\). On catalytic hydrogenation over palladium, it reacts with only 1 molar equivalent of \(\mathrm{H_2}\). Compound A also undergoes reaction with ozone, followed by zinc treatment, to yield a symmetrical diketone, B \(\mathrm{(C_{10}H_{16}O_2)}\). (a) How many rings does A have? (b) What are the structures of A and B? (c) Write the reactions. Equation Transcription: Text Transcription: C_{10}H_{16} H_2 (C_{10}H_{16}O_2)

An unknown hydrocarbon A with the formula \(\mathrm {C_6H_{12}}\) reacts with 1 molar equivalent of \(\mathrm {H_2}\) over a palladium catalyst. Hydrocarbon A also reacts with \(\mathrm {OsO_4}\) to give diol B. When oxidized with \(\mathrm {KMnO_4}\) in acidic solution, A gives two fragments. One fragment is propanoic acid, \(\mathrm {CH_3CH_2CO_2H}\), and the other fragment is ketone C. What are the structures of A, B, and C? Write all reactions, and show your reasoning. Equation Transcription: Text Transcription: C_6H_{12} H_2 OsO_4 KMnO_4 CH_3CH_2CO_2H

Using an oxidative cleavage reaction, explain how you would distinguish between the following two isomeric dienes:

Compound A, \(\mathrm {C_{10}H_{18}O}\), undergoes reaction with dilute \(\mathrm {H_2SO_4}\) at \(\mathrm {50\ ^\circ C}\) to yield a mixture of two alkenes, \(\mathrm {C_{10}H_{16}}\). The major alkene product, B, gives only cyclopentanone after ozone treatment followed by reduction with zinc in acetic acid. Identify A and B, and write the reactions. Equation Transcription: Text Transcription: C_{10}H_{18}O H_2SO_4 50^oC C_{10}H_{16}

Draw the structure of a hydrocarbon that absorbs 2 molar equivalents of \(\mathrm {H_2}\) on catalytic hydrogenation and gives only butanedial on ozonolysis. Equation Transcription: Text Transcription: H_2 HCCH_2CH_2CH

Simmons–Smith reaction of cyclohexene with diiodomethane gives a single cyclopropane product, but the analogous reaction of cyclohexene with 1,1-diiodoethane gives (in low yield) a mixture of two isomeric methylcyclopropane products. What are the two products, and how do they differ?

The sex attractant of the common housely is a hydrocarbon with the formula \(\mathrm {C_{23}H_{46}}\). On treatment with aqueous acidic \(\mathrm {KMnO_{4}}\), two products are obtained, \(\mathrm {CH_3(CH_2)_{12}CO_2H}\) and \(\mathrm {CH_3(CH_2)_{7}CO_2H}\). Propose a structure. Equation Transcription: Text Transcription: C_{23}H_{46} KMnO_{4} CH_3(CH_2)_{12}CO_2H CH_3(CH_2)_{7}CO_2H

Compound A has the formula \(\mathrm {C_8H_8}\). It reacts rapidly with \(\mathrm {KMnO_4}\) to give \(\mathrm {CO_2}\) and a carboxylic acid, B \(\mathrm {(C_7H_6O_2)}\), but reacts with only 1 molar equivalent of \(\mathrm {H_2}\) on catalytic hydrogenation over a palladium catalyst. On hydrogenation under conditions that reduce aromatic rings, 4 equivalents of \(\mathrm {H_2}\) are taken up and hydrocarbon C \(\mathrm {(C_8H_{16})}\) is produced. What are the structures of A, B, and C? Write the reactions. Equation Transcription: Text Transcription: C_8H_8 KMnO_4 CO_2 (C_7H_6O_2) H_2 H_2 (C_8H_{16})

How would you distinguish between the following pairs of compounds using simple chemical tests? Tell what you would do and what you would see. (a) Cyclopentene and cyclopentane (b) 2-Hexene and benzene

\(\alpha\)-Terpinene, \(\mathrm {C_{10}H_{16}}\), is a pleasant-smelling hydrocarbon that has been isolated from oil of marjoram. On hydrogenation over a palladium catalyst, a-terpinene reacts with 2 molar equivalents of \(\mathrm {H_2}\) to yield a hydrocarbon, \(\mathrm {C_{10}H_{20}}\). On ozonolysis, followed by reduction with zinc and acetic acid, \(\alpha\)-terpinene yields two products, glyoxal and 6-methyl-2,5-heptanedione. (a) How many degrees of unsaturation does \(\alpha\)-terpinene have? (b) How many double bonds and how many rings does it have? (c) Propose a structure for a-terpinene. Equation Transcription: Text Transcription: alpha C_{10}H_{16} alpha H_2 C_{10}H_{20} alpha CH_3CCH_2CH_2CCHCH_3 CH_3

Evidence that cleavage of 1,2-diols by \(\mathrm {HIO_4}\) occurs through a five membered cyclic periodate intermediate is based on kinetic data—the measurement of reaction rates. When diols A and B were prepared and the rates of their reaction with \(\mathrm {HIO_4}\) were measured, it was found that diol A cleaved approximately 1 million times faster than diol B. Make molecular models of A and B and of potential cyclic periodate intermediates, and then explain the kinetic results ________________ Equation Transcription: Text Transcription: HIO_4 HIO_4

Reaction of HBr with 3-methylcyclohexene yields a mixture of four products: cis- and trans-1-bromo-3-methylcyclohexane and cis- and trans-1-bromo-2-methylcyclohexane. The analogous reaction of HBr with 3-bromocyclo hexene yields trans-1,2-dibromocyclohexane as the sole product. Draw structures of the possible intermediates, and then explain why only a single product is formed in this reaction. Equation Transcription: Text Transcription: CH_3 CH_3 CH_3

We’ll see in the next chapter that alkynes undergo many of the same reactions that alkenes do. What product might you expect from each of the following reactions? Equation Transcription: Text Transcription: CH_3 CH_3CHCH_2CH_2CCH Br_2 H_2,Pd/C

Hydroxylation of cis-2-butene with \(\mathrm {OsO_4}\) yields a different product than hydroxylation of trans-2-butene. Draw the structure, show the stereochemistry of each product, and explain the difference between them. Equation Transcription: Text Transcription: OsO_4

Compound A, \(\mathrm {C_{11}H_{16}O}\), was found to be an optically active alcohol. Despite its apparent unsaturation, no hydrogen was absorbed on catalytic reduction over a palladium catalyst. On treatment of A with dilute sulfuric acid, dehydration occurred and an optically inactive alkene B, \(\mathrm {C_{11}H_{14}}\), was the major product. Alkene B, on ozonolysis, gave two products. One product was identified as propanal, \(\mathrm {CH_3CH_2CHO}\). Compound C, the other product, was shown to be a ketone, \(\mathrm {C_8H_8O}\). How many degrees of unsaturation does A have? Write the reactions, and identify A, B, and C. Equation Transcription: Text Transcription: C_{11}H_{16}O C_{11}H_{14} CH_3CH_2CHO C_8H_8O