Draw a stepwise mechanism for the following reaction. H2O H3O+ O + OH OH

Rank the compounds in each group in order of increasing reactivity towards nucleophilic attack. a. CH3CH O (CH3) CH2 O 2C O b. O O O

Explain why benzaldehyde is less reactive than cyclohexanecarbaldehyde towards nucleophilic attack. CHO benzaldehyde CHO cyclohexanecarbaldehyde

Give the IUPAC name for each aldehyde. a. (CH3)3CC(CH3)2CH2CHO b. CHO c. CHO Cl Cl

Give the structure corresponding to each IUPAC name. a. 2-isobutyl-3-isopropylhexanal c. 1-methylcyclopropanecarbaldehyde b. trans-3-methylcyclopentanecarbaldehyde d. 3,6-diethylnonanal

Give the IUPAC name for each ketone. a. O b. O (CH3)3C CH3 c. (CH3)3CCOC(CH3)3

Give the structure corresponding to each name: (a) sec-butyl ethyl ketone; (b) methyl vinyl ketone; (c) p-ethylacetophenone; (d) 3-benzoyl-2-benzylcyclopentanone; (e) 6,6-dimethyl-2-cyclohexenone; (f) 3-ethyl-5-hexenal.

Give the IUPAC name (including any E,Z designation) for each unsaturated aldehyde. Neral is obtained from lemon grass, and the unmistakable odor of a freshly cut cucumber is due largely to cucumber aldehyde. a. CHO neral b. CHO cucumber aldehyde

The boiling point of 2-butanone (80 C) is signifi cantly higher than the boiling point of diethyl ether (35 C), even though both compounds exhibit dipoledipole interactions and have comparable molecular weights. Offer an explanation.

Which carbonyl group in each pair absorbs at a higher frequency? a. CHO or CHO b. orO O

Draw the structure of all constitutional isomers that contain a ketone and have molecular formula C5H10O. Give the IUPAC name for each isomer and state how 13C NMR spectroscopy could be used to distinguish these isomers.

What reagents are needed to convert each compound into butanal (CH3CH2CH2CHO): (a) CH3CH2CH2COOCH3; (b) CH3CH2CH2CH2OH; (c) HC CCH2CH3; (d) CH3CH2CH2CH CHCH2CH2CH3?

What reagents are needed to convert each compound into acetophenone (C6H5COCH3): (a) benzene; (b) C6H5COCl; (c) C6H5C CH?

What alkene would yield 2,2-dimethoxy-1,3-cyclopentanedicarbaldehyde on treatment with O3 followed by (CH3)2S? OCH3 OHC CH3O 2,2-dimethoxy-1,3-cyclopentanedicarbaldehyde

Why does equilibrium favor the product when H adds to a carbonyl group?

Draw the products of each reaction. Include all stereoisomers formed. a. NaBH4 CH3OH O b. [1] CH CHMgBr 2 (CH [2] H2O 3)3C

Draw the products of each reaction. a. CHO NaCN HCl b. H3O+ OH , CN

What cyanohydrin and carbonyl compound are formed when amygdalin is metabolized in a similar manner?

Draw the products of the following Wittig reactions. a. + Ph3P CH2 (CH3)2C O b. O + Ph3P CHCH2CH2CH2CH3

Draw the products (including stereoisomers) formed when benzaldehyde (C6H5CHO) is treated with each Wittig reagent: (a) Ph3P CHCH2CH3; (b) Ph3P CHC6H5; (c) Ph3P CHCOOCH3.

What starting materials are needed to prepare each alkene by a Wittig reaction? When there are two possible routes, indicate which route, if any, is preferred: (a) (CH3)2C CHCH2CH3; (b) CH3CH2CH CHCH2CH3; (c) C6H5CH CHCH3

Show two methods to synthesize each alkene: a one-step method using a Wittig reagent, and a two-step method that forms a carboncarbon bond with an organometallic reagent in one of the steps. a. O b. O CHC6H5

Draw the product formed when CH3CH2CH2CH2NH2 reacts with each carbonyl compound in the presence of mild acid. a. CHO b. O c. O

What 1 amine and carbonyl compound are needed to prepare each imine? a. C NCH2CH2CH3 CH3 H b. CH3 N

Draw a stepwise mechanism for the formation of rhodopsin from 11-cis-retinal and an NH2 group in opsin.

What two enamines are formed when 2-methylcyclohexanone is treated with (CH3)2NH?

Explain why benzaldehyde cannot form an enamine with a 2 amine.

What carbonyl compound and amine are formed by the hydrolysis of each compound? a. CH N b. CH2 N CH3 c. (CH3)2NCH C(CH3)2

Draw a stepwise mechanism for the following reaction. H2O H3O+ O + OH OH

Draw the products of each reaction. a. TsOH 2 CH3OH O b. TsOH + O HO OH

Label each compound as an acetal, a hemiacetal, or an ether. a. OCH3 OCH3 b. OCH3 OCH3 c. O O CH3 CH3 d. OH OCH3

Draw a stepwise mechanism for the following reaction. + HOCH2CH2OH O + H2O TsOH O O

Draw the products of each reaction. a. CH3O H2O H2SO4 OCH3 + c. H2O H2SO4 + O O b. H2O H2SO4

Safrole is a naturally occurring acetal isolated from sassafras plants. Once used as a common food additive in root beer and other beverages, it is now banned because it is carcinogenic. What compounds are formed when safrole is hydrolyzed with aqueous acid? safrole O O

How would you use a protecting group to carry out the following transformation? O O OH COOCH2CH3

What lactol (cyclic hemiacetal) is formed from intramolecular cyclization of each hydroxy aldehyde? a. O HO H b. O OH H

Draw the products of each reaction. a. OH CH3CH2OH O + H+ b. OH HO HO CH3CH2OH O + H+

a. How many stereogenic centers are present in -D-galactose? b. Label the hemiacetal carbon in -D-galactose. c. Draw the structure of -D-galactose. d. Draw the structure of the polyhydroxy aldehyde that cyclizes to - and -D-galactose. e. From what you learned in Section 21.16B, what product(s) is (are) formed when -D-galactose is treated with CH3OH and an acid catalyst?

Give the IUPAC name for each compound. a. (CH3)3CCH2CHO d. CHO g. CHO CH2Ph j. CHO b. O Cl e. O h. CH(CH3)2 C O (CH3)3C k. O c. O Ph f. O CH3 (CH3)2CH i. CH3 NO2 O l. CHO

Give the structure corresponding to each name. a. 2-methyl-3-phenylbutanal e. 3-benzoylcyclopentanone i. 2-sec-butyl-3-cyclopentenone b. dipropyl ketone f. 2-formylcyclopentanone j. 5,6-dimethyl-1-cyclohexenecarbaldehyde c. 3,3-dimethylcyclohexanecarbaldehyde g. (3R)-3-methyl-2-heptanone d. -methoxypropionaldehyde h. m-acetylbenzaldehyde

Including stereoisomers, draw the 11 aldehydes with molecular formula C6H12O, and give the IUPAC name (with any needed R,S designation) for each compound.

Draw the product formed when phenylacetaldehyde (C6H5CH2CHO) is treated with each reagent. Phenylacetaldehyde is partly responsible for the fragrance of the fl owers of the plumeria tree, which is native to the tropical and subtropical Americas. a. NaBH4, CH3OH e. Ph3P CHCH3 b. [1] LiAlH4; [2] H2O f. (CH3)2CHNH2, mild acid i. NH, mild acid c. [1] CH3MgBr; [2] H2O g. (CH3CH2)2NH, mild acid d. NaCN, HCl h. CH3CH2OH (excess), H+ j. HOCH2CH2OH, H+

Answer Problem 21.45 using 2-heptanone (CH3COCH2CH2CH2CH2CH3) as starting material. 2-Heptanone is partly responsible for the odor of bleu cheese.

Draw the products formed in each Wittig reaction. Draw all stereoisomers formed when a mixture of products results. a. O Ph3P CHCH2CH3 c. Ph3P CHCOOCH3 CHO b. Ph3P CHO d. P

Draw the products formed in each reaction sequence. a. CH3CH2Cl [1] Ph3P [2] BuLi [3] (CH3)2C O b. C6H5CH2Br [1] Ph3P [2] BuLi [3] C6H5CH2CH2CHO c. [1] Ph3P [2] BuLi [3] CH3CH2CH2CHO CH2Cl

What alkyl halide is needed to prepare each Wittig reagent? a. Ph3P CHCH2CH2CH3 b. Ph3P C(CH2CH2CH3)2 c. Ph3P CHCH CH2

Draw the products of each reaction. a. CH3CH2CHO + H2N mild acid e. H3O+, CN C6H5 C HO C6H5 b. O H+ HOCH2CH2OH f. O H+ CH3CH2OH OH c. N H3O+ g. N H3O+ d. N H + mild acid O C6H5 h. H3O+ CH3O OCH3 OCH3

What carbonyl compound and alcohol are formed by hydrolysis of each acetal? a. CH3CH2O OCH2CH3 b. CH3O OCH3 OCH3 OCH3 c. OCH2CH3 O

Identify the lettered intermediates in the following reaction sequence. When a mixture of ortho and para products results in electrophilic aromatic substitution, consider the para product only. The 1 H NMR spectrum of G shows two singlets at 2.6 and 8.18 ppm. Br2 FeBr3 A CH3COCl AlCl3 B C H+ Mg D E [1] CH3CHO [2] H2O F G PCC H2O H+ HOCH2CH2OH

Draw all stereoisomers formed in each reaction. a. CH3CH2CH2CHO Ph3P CHCH2CH2CH3 c. CH3CH2 NaBH4 CH3OH O b. NaCN HCl O d. HO O CH3OH HCl OH

Hydroxy aldehydes A and B readily cyclize to form hemiacetals. Draw the stereoisomers formed in this reaction from both A and B. Explain why this process gives an optically inactive product mixture from A, and an optically active product mixture from B. A HO H B CHO HO CHO

Etoposide, sold under the trade name of Etopophos, is used for the treatment of lung cancer, testicular cancer, and lymphomas. (a) Locate the acetals in etoposide. (b) What products are formed when all of the acetals are hydrolyzed with aqueous acid? H O O O O etoposide O O CH3O OCH3 O H H H OH OH HO O

Rank the compounds in each group in order of increasing reactivity in nucleophilic addition. a. H O O O b. O O O

Explain why a gem-diol is the major species present at equilibrium when cyclopropanone is dissolved in H2O.

Consider the para-substituted aromatic ketones, NO2C6H4COCH3 (p-nitroacetophenone) and CH3OC6H4COCH3 (p-methoxyacetophenone). a. Which carbonyl compound is more stable? b. Which compound forms the higher percentage of hydrate at equilibrium? c. Which compound exhibits a carbonyl absorption at higher wavenumber in its IR spectrum? Explain your reasoning in each part.

What carbonyl compound and amine or alcohol are needed to prepare each product? a. N b. N c. O O d. CH3O OCH3 OCH3

What reagents are needed to convert each compound to benzaldehyde (C6H5CHO)? More than one step may be required. a. C6H5CH2OH e. C6H5CH3 b. C6H5COCl f. C6H5CH CH2 c. C6H5COOCH3 g. C6H5CH NCH2CH2CH3 d. C6H5COOH h. C6H5CH(OCH2CH3)2

What reagents are needed to convert each compound to 2-butanone (CH3COCH2CH3)? a. OH b. Cl O c. CH3COCl d. CH3CH2C CH e. CH3C CCH3

Show two different methods to carry out each transformation: a one-step method using a Wittig reagent, and a two-step method using a Grignard reagent. Which route, if any, is preferred for each compound? a. O b. CHO

Devise a synthesis of each alkene using a Wittig reaction to form the double bond. You may use benzene and organic alcohols having four or fewer carbons as starting materials and any required reagents. a. CH3CH2CH2CH CHCH3 b. C6H5CH CHCH2CH2CH3 c. (CH3)2C CHCH(CH3)2

Devise a synthesis of each compound from cyclohexene and organic alcohols. You may use any other required organic or inorganic reagents. a. O O b. CHCH2CH3 c. NCH2CH2CH3 d. C(OCH2CH3)2 2 e. O O

Devise a synthesis of each compound from the given starting materials. You may also use organic alcohols having four or fewer carbons, and any organic or inorganic reagents. a. CH CH b. and CH C(CH3) CH3O CH 3 OH

Devise a synthesis of each compound from 5-hydroxy-2-pentanone (CH3COCH2CH2CH2OH) as starting material. You may also use alcohols having three or fewer carbons and any required organic or inorganic reagents. a. OH OH b. CH (E/Z mixture) CHCH2CH3 O

Devise a synthesis of each compound from ethanol (CH3CH2OH) as the only source of carbon atoms. You may use any other organic or inorganic reagents you choose. a. OCH2CH3 OCH2CH3 CH2CH3 CH3 C b. CCCH O O CH3

Design a stepwise synthesis to convert cyclopentanone and 4-bromobutanal to hydroxy aldehyde A. + OH CHO cyclopentanone 4-bromobutanal A O Br CHO

Besides the tert-butyldimethylsilyl ethers introduced in Chapter 20, there are many other widely used alcohol protecting groups. For example, an alcohol such as cyclohexanol can be converted to a methoxy methyl ether (a MOM protecting group) by treatment with base and chloromethyl methyl ether, ClCH2OCH3. The protecting group can be removed by treatment with aqueous acid. cyclohexanol methoxy methyl ether OH H3O+ [1] NaH [2] ClCH2OCH3 OCH2OCH3 a. Write a stepwise mechanism for the formation of a MOM ether from cyclohexanol. b. What functional group comprises a MOM ether? c. Besides cyclohexanol, what other products are formed by aqueous hydrolysis of the MOM ether? Draw a stepwise mechanism that accounts for formation of each product.

Draw a stepwise mechanism for each reaction. a. H N H3O+ O NH3 + b. O H mild acid O H + + NH2 NH2 2 H2O N N

Treatment of (HOCH2CH2CH2CH2)2CO with acid forms a product of molecular formula C9H16O2 and a molecule of water. Draw the structure of the product and explain how it is formed.

When acetone is dissolved in aqueous acid containing isotopically labeled H2O (H2 18O), the carbonyl group becomes labeled with 18O. Draw a mechanism that explains this observation. H2 18O H+ O 18O

Draw a stepwise mechanism for each reaction. a. O HOCH2CH2CH2CHO H3O+ OCH2CH3 + CH3CH2OH b. O O H3O+ C6H5CHO C6H5 OH + + H2O

Another way to synthesize cyclic acetals uses enol ethers (not carbonyl compounds) as starting materials. Draw a stepwise mechanism for the following synthesis of an acetal from an enol ether and ethylene glycol. + O O + TsOH enol ether ethylene glycol acetal CH3OH OCH3 HO OH

Salsolinol is a naturally occurring compound found in bananas, chocolate, and several foods derived from plant sources. Salsolinol is also formed in the body when acetaldehyde, an oxidation product of the ethanol ingested in an alcoholic beverage, reacts with dopamine, a neurotransmitter. Draw a stepwise mechanism for the formation of salsolinol in the following reaction. dopamine NH2 CH3CHO CH3 acetaldehyde mild acid salsolinol NH HO HO HO HO + + H2O

Sulfur ylides, like Wittig reagents, are useful intermediates in organic synthesis. Sulfur ylides are formed by the treatment of sulfonium salts with butyllithium. They react with carbonyl compounds to form epoxides. Draw the mechanism for formation of epoxide X from cyclohexanone using a sulfur ylide. (CH3)2S O X sulfonium salt sulfur ylide H Bu Li X + CH2 (CH3)2S + CH2 + Bu H + LiX O (CH3) + 2S

Reaction of 5,5-dimethoxy-2-pentanone with methylmagnesium iodide followed by treatment with aqueous acid forms cyclic hemiacetal Y. Draw a stepwise mechanism that illustrates how Y is formed. O O OH Y OCH3 OCH3 5,5-dimethoxy-2-pentanone [1] CH3MgI [2] H3O+

Although the carbonyl absorption of cyclic ketones generally shifts to higher wavenumber with decreasing ring size, the C O of cyclopropenone absorbs at lower wavenumber in its IR spectrum than the C O of cyclohexenone. Explain this observation by using the principles of aromaticity learned in Chapter 17. O cyclopropenone (1640 cm1) 2-cyclohexenone (1685 cm1)

How would the compounds in each pair differ in their IR spectra: (a) CH3(CH2)4CHO and CH3(CH2)3COCH3; (b) C6H5CH2COCH3 and C6H5COCH2CH3; (c) cyclohexanone and 2-methylcyclopentanone?

Use the 1 H NMR and IR data to determine the structure of each compound. Compound A Molecular formula: C5H10O IR absorptions at 1728, 2791, and 2700 cm1 1 H NMR data: 1.08 (singlet, 9 H) and 9.48 (singlet, 1 H) ppm Compound B Molecular formula: C5H10O IR absorption at 1718 cm1 1 H NMR data: 1.10 (doublet, 6 H), 2.14 (singlet, 3 H), and 2.58 (septet, 1 H) ppm Compound C Molecular formula: C10H12O IR absorption at 1686 cm1 1 H NMR data: 1.21 (triplet, 3 H), 2.39 (singlet, 3 H), 2.95 (quartet, 2 H), 7.24 (doublet, 2 H), and 7.85 (doublet, 2 H) ppm Compound D Molecular formula: C10H12O IR absorption at 1719 cm1 1 H NMR data: 1.02 (triplet, 3 H), 2.45 (quartet, 2 H), 3.67 (singlet, 2 H), and 7.067.48 (multiplet, PDF

A solution of acetone [(CH3)2C O] in ethanol (CH3CH2OH) in the presence of a trace of acid was allowed to stand for several days, and a new compound of molecular formula C7H16O2 was formed. The IR spectrum showed only one major peak in the functional group region around 3000 cm1, and the 1 H NMR spectrum is given here. What is the structure of the product? 1H NMR (C7H16O2) 4 H 6 H 6 H ppm 9 0

Compounds A and B have molecular formula C9H10O. Identify their structures from the 1 H NMR and IR spectra given. ppm 11 10 9 8 7 6 5 4 3 2 1 0 1H NMR of A 2 H 3 H 1 H 4 H Wavenumber (cm1) % Transmittance 100 50 0 4000 3500 3000 2500 2000 1500 1000 500 IR of A ppm 11 10 9 8 7 6 5 4 3 2 1 0 1H NMR of B 5 H 1 H 2 H 2 H IR of B Wavenumber (cm1) % Transmittance 100 50 0 4000 3500 3000 2500 2000 1500 1000 500

An unknown compound C of molecular formula C6H12O3 exhibits a strong absorption in its IR spectrum at 1718 cm1 and the given 1 H NMR spectrum. What is the structure of C? 0 ppm 1H NMR of C 8 7 7 40 14 21 654321

An unknown compound D exhibits a strong absorption in its IR spectrum at 1692 cm1. The mass spectrum of D shows a molecular ion at m/z = 150 and a base peak at 121. The 1 H NMR spectrum of D is shown below. What is the structure of D? 0 ppm 891011 7 2 H 2 H 1 H 2 H 3 H 1H NMR of D 654321

Draw the structure of the acyclic polyhydroxy aldehyde that cyclizes to each hemiacetal. a. OH OH OH HO HO O b. OH OH HO HO HO O

Draw a stepwise mechanism for the following reaction. O O OH H+ O O OH

Brevicomin, the aggregation pheromone of the western pine bark beetle, contains a bicyclic bridged ring system and is prepared by the acid-catalyzed cyclization of 6,7-dihydroxy-2-nonanone. a. Suggest a structure for brevicomin. b. Devise a synthesis of 6,7-dihydroxy-2-nonanone from 6-bromo-2-hexanone. You may also use three-carbon alcohols and any required organic or inorganic reagents. Br 6-bromo-2-hexanone O 6,7-dihydroxy-2-nonanone O OH several steps brevicomin H3O+ OH

Maltose is a carbohydrate present in malt, the liquid obtained from barley and other grains. Although maltose has numerous functional groups, its reactions are explained by the same principles we have already encountered. O OH O HO HO HO O OH HO HO OH maltose a. Label the acetal and hemiacetal carbons. b. What products are formed when maltose is treated with each of the following reagents: [1] H3O+ ; [2] CH3OH and HCl; [3] excess NaH, then excess CH3I? c. Draw the products formed when the compound formed in Reaction [3] of part (b) is treated with aqueous acid. The reactions in parts (b) and (c) are used to determine structural features of carbohydrates like maltose. We will learn much more about maltose and similar carbohydrates in Chapter 27.