?Choose which member in each of the following pairs reacts faster or has the more

The common names and structural formulas of a few aldehydes follow. Provide an IUPAC name for each.

Can catalytic hydrogenation be used to reduce a carboxylic acid to a primary alcohol in the first step of the sequence RCO2H ? RCH2OH ? RCHO?

(a) Show how 2-butanone could be prepared by a procedure in which all of the carbons originate in acetic acid (CH3CO2H). (b) Two species of ants found near the Mediterranean use 2-methyl-4-heptanone as an alarm pheromone. Suggest a synthesis of this compound from two 4-carbon alcohols.

Gynocardin is a naturally occurring cyanogenic glycoside having the structure shown. What cyanohydrin would you expect to be formed on hydrolysis of gynocardin, and to what ketone does this cyanohydrin correspond?

Acetal formation is a characteristic reaction of aldehydes and ketones, but not of carboxylic acids. Use retrosynthetic analysis to show how you could use a cyclic acetal protecting group in the following synthesis, then write equations for the procedure showing the necessary reagents.

Write the structure of the aminal or hemiaminal intermediate and the imine product formed in the reaction of each of the following: (a) Acetaldehyde and benzylamine, C6H5CH2NH2 (b) Benzaldehyde and butylamine, CH3CH2CH2CH2NH2 (c) Cyclohexanone and tert-butylamine, (CH3)3CNH2

Not all biological reactions of amino acids involving imine intermediates require pyridoxal phosphate. The first step in the conversion of proline to glutamic acid is an oxidation giving the imine shown. Once formed, this imine undergoes hydrolysis to a species having the molecular formula C5H9NO3, which then goes on to produce glutamic acid. Suggest a structure for the C5H9NO3 species. (Hint: There are two reasonable possibilities; one is a hemiaminal, the other is not cyclic.)

The product of the following reaction is a heterocyclic aromatic compound. What is its structure?

Write the structure of the hemiaminal intermediate and the enamine product formed in the reaction of each of the following. (a) Propanal and dimethylamine (b) 3-Pentanone and pyrrolidine

Identify the alkene formed in each of the following reactions:

Write equations outlining two different syntheses of 3-methyl-3-heptene using 1-butanol and 2-butanol as the source of all of the carbons.

(a) Write structural formulas and provide IUPAC names for all the isomeric aldehydes and ketones that have the molecular formula C5H10O. Include stereoisomers. (b) Which of the isomers in part (a) yield chiral alcohols on reaction with sodium borohydride? (c) Which of the isomers in part (a) yield chiral alcohols on reaction with methylmagnesium iodide?

The African dwarf crocodile secretes a volatile substance believed to be a sex pheromone. It is a mixture of two stereoisomers, one of which is shown: (a) Give the IUPAC name for this compound, including R and S descriptors for its chirality centers. (b) One component of the scent substance has the S configuration at both chirality centers. How is this compound related to the one shown? Are the compounds enantiomers or diastereomers?

Compounds that contain a carbon–nitrogen double bond are capable of stereoisomerism much like that seen in alkenes. The structures are stereoisomeric. Specifying stereochemistry in these systems is best done by using E–Z descriptors and considering the nitrogen lone pair to be the lowest priority group. Write the structures, clearly showing stereochemistry, of the following: (a) (Z)-CH3CH=NCH3 (b) (E)-Acetaldehyde oxime (c) (Z)-2-Butanone hydrazone (d) (E)-Acetophenone semicarbazone

Predict the product of the reaction of propanal with each of the following: (a) Lithium aluminum hydride, followed by water (b) Sodium borohydride, methanol (c) Hydrogen (nickel catalyst) (d) Methylmagnesium iodide, followed by dilute acid (e) Sodium acetylide, followed by dilute acid (f) Phenyllithium, followed by dilute acid (g) Methanol containing dissolved hydrogen chloride (h) Ethylene glycol, p-toluenesulfonic acid, benzene (i) Aniline (C6H5NH2) ( j) Dimethylamine, p-toluenesulfonic acid, benzene (k) Hydroxylamine (l) Hydrazine (m) Product of part (l) heated in triethylene glycol with sodium hydroxide (n) p-Nitrophenylhydrazine (o) Semicarbazide (p) Ethylidenetriphenylphosphorane \(\left[\left(\mathrm{C}_{6} \mathrm{H}_{5}\right)_{3} \stackrel{+}{\mathrm{P}}-\overline{\ddot{\mathrm{C}}} \mathrm{HCH}_{3}\right]\) (q) Sodium cyanide with addition of sulfuric acid (r) Chromic acid Text Transcription: [(C_6H_5)_3 stackrel +P - overline ddot CHCH_3]

Hydride reduction (with LiAlH4 or NaBH4) of each of the following ketones has been reported in the chemical literature and gives a mixture of two diastereomeric alcohols in each case. Give the structures of both alcohol products for each ketone. (a) (S)-3-Phenyl-2-butanone (b) 4-tert-Butylcyclohexanone

Choose which member in each of the following pairs reacts faster or has the more favorable equilibrium constant for reaction with the indicated reagent. Explain your reasoning. (c) Acetone or 3,3-dimethyl-2-butanone (equilibrium constant for cyanohydrin formation) (d) Acetone or 3,3-dimethyl-2-butanone (rate of reduction with sodium borohydride) (e) CH2(OCH2CH3)2 or (CH3)2C(OCH2CH3)2 (rate of acid-catalyzed hydrolysis)

Equilibrium constants for the dissociation (Kdiss) of cyanohydrins according to the equation have been measured for a number of cyanohydrins. Which cyanohydrin in each of the following pairs has the greater dissociation constant?

Each of the following reactions has been reported in the chemical literature and gives a single organic product in good yield. What is the principal product in each reaction?

Wolff–Kishner reduction (hydrazine, KOH, ethylene glycol, 130°C) of the compound shown gave compound A. Treatment of compound A with m-chloroperoxybenzoic acid (MCPBA) gave compound B, which on reduction with lithium aluminum hydride gave compound C. Oxidation of compound C with chromic acid gave compound D (C9H14O). Identify compounds A through D in this sequence.

On standing in 17O-labeled water, both formaldehyde and its hydrate are found to have incorporated the 17O isotope of oxygen. Suggest a reasonable explanation for this observation.

Reaction of benzaldehyde with 1,2-octanediol in benzene containing a small amount of p-toluenesulfonic acid yields almost equal quantities of two products in a combined yield of 94%. Both products have the molecular formula C15H22O2. Suggest reasonable structures for these products.

Compounds that contain both carbonyl and alcohol functional groups are often more stable as cyclic hemiacetals or cyclic acetals than as open-chain compounds. Examples of several of these are shown. Deduce the structure of the open-chain form of each.

The OH groups at C-4 and C-6 of methyl ?-d-glucopyranoside can be protected by conversion to a benzylidene acetal. What reagents are needed for this conversion?

(a) Benzoyl chloride and benzene (b) Benzyl alcohol and bromobenzene (c) Bromodiphenylmethane, (C6H5)2CHBr (d) Dimethoxydiphenylmethane, (C6H5)2C(OCH3)2 (e) 1,1,2,2-Tetraphenylethene, (C6H5)2C = C(C6H5)2

Studies of the sex pheromone of the Douglas fir tussock moth required the synthesis of (E)-1,6-henicosadien-11-one. Outline a synthesis of this ketone using (E)-5,10-undecadien-1-ol and 1-decanol as sources of all of the carbons.

The sex attractant of the female winter moth has been identified as the tetraene CH3(CH2)8CH=CHCH2CH=CHCH2CH=CHCH=CH2. Devise a synthesis of this material from 3,6-hexadecadien-1-ol and allyl alcohol.

Leukotrienes are substances produced in the body that may be responsible for inflammatory effects. As part of a synthesis of one of these, compound A reacted with the Wittig reagent shown to give B along with some of its Z stereoisomer. Explain the origin of these compounds.

Syntheses of each of the following compounds have been reported in the chemical literature. Using the indicated starting material and any necessary organic or inorganic reagents, describe short sequences of reactions that would be appropriate for each transformation

After heating compound A with a catalytic amount of p-toluenesulfonic acid and water in dichloromethane (45C) for 24 hr, compound C was isolated in 79% yield Demonstrate your understanding of the overall reaction by identifying the key intermediate (compound B). What other compound is formed in the reaction?

Suggest a reasonable mechanism for each of the following reactions:

Alcohol functions can be protected as tetrahydropyranyl ethers (THPs) by acid-catalyzed addition to dihydropyran according to the equation: Addition of the alcohol to dihydropyran is regiospecific in that I is formed to the exclusion of II. Suggest a mechanistic reason for the observed regioselectivity.

A compound has the molecular formula C4H8O and contains a carbonyl group. Identify the compound on the basis of its 1H NMR spectrum shown in Figure 18.14.

A compound (C7H14O) has a strong peak in its IR spectrum at 1710 cm–1. Its 1H NMR spectrum consists of three singlets in the ratio 9:3:2 at ? 1.0, 2.1, and 2.3, respectively. Identify the compound.

Compounds A and B are isomeric diketones of molecular formula C6H10O2. The 1H NMR spectrum of compound A contains two signals, both singlets, at \(\delta\) 2.2 (six protons) and 2.8 (four protons). The 1H NMR spectrum of compound B contains two signals, one at \(\delta\) 1.3 (triplet, six protons) and the other at \(\delta\) 2.8 (quartet, four protons). What are the structures of compounds A and B? Text Transcription: delta

A compound (C11H14O) has the (a) IR and (b) 300-MHz 1H NMR spectra shown in Figure 18.15. What is the structure of this compound?

A compound is a ketone of molecular formula C7H14O. Its 13C NMR spectrum is shown in Figure 18.16. What is the structure of the compound?

Compound A and compound B are isomers having the molecular formula C10H12O. The mass spectrum of each compound contains an abundant peak at m/z 105. The 13C NMR spectra of compound A (Figure 18.17) and compound B (Figure 18.18) are shown. Identify these two isomers.

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. Which of the following are not intermediates in the Baeyer–Villiger oxidation of cyclohexyl methyl ketone with peroxybenzoic acid? A. I and II B. III and IV C. I and III D. II and IV

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. Which is the product of the following reaction?

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. If the configuration of the chirality center is R in the reactant in Problem 18.53, what will the configuration be at this carbon in the product? A. R B. S C. an equal mixture of R and S D. an unequal mixture of R and S

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. The Baeyer–Villiger oxidations of the substituted diphenyl ketones proceeds as indicated because: A. The electron-withdrawing nitro group retards the migration of the phenyl ring to which it is attached. B. The electron-releasing methoxy group accelerates the migration of the phenyl ring to which it is attached. C. Both A and B D. Neither A nor B. The regioselectivity is due to steric effects.

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. A key step in the laboratory synthesis of prostaglandins involves the sequence shown here. What is the identity of compound X?

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. A reaction analogous to the Baeyer–Villiger reaction occurs in living systems through the action of certain bacterial enzymes. A preparation of the S enantiomer of compound Y has been described using a bacterial cyclohexanone monooxygenase enzyme system. What is compound X?

The oxidation of ketones with peroxy acids is both novel and synthetically useful. An oxygen from the peroxy acid is inserted between the ketone carbonyl group and one of its attached carbons to give an ester. First described by Adolf von Baeyer and Victor Villiger in 1899, reactions of this type are known as Baeyer–Villiger oxidations. The reaction is regioselective; oxygen insertion occurs between the carbonyl carbon and the larger (R) of the two groups attached to it. Methyl ketones ( R = CH3 ) give esters of acetic acid; The mechanism of the Baeyer–Villiger reaction begins with nucleophilic addition of the peroxy acid to the carbonyl group. After protonation by an acid catalyst (either the peroxy acid or a carboxylic acid), the conjugate acid of the product of the first step rearranges by an alkyl group migration. Normally, it is the larger of the two groups originally bonded to the carbonyl group that migrates. The reaction is stereospecific; the alkyl group migrates with retention of configuration, as illustrated for the oxidation of cis-1-acetyl-2-methylcyclopentane; only the cis product is obtained. When the ketone is cyclic, a cyclic ester, or lactone, is formed. Cyclobutanone is oxidized to a lactone by the Baeyer–Villiger reaction. If compound Y in the preceding problem is prepared by treatment of compound X with peroxybenzoic acid, compound Y would be obtained as: A. Only the S enantiomer B. Only the R enantiomer C. A racemic mixture D. An unequal mixture of R and S enantiomers

Convert each of the following functional class IUPAC names to a substitutive name. (a) Dibenzyl ketone (b) Ethyl isopropyl ketone (c) Methyl 2,2-dimethylpropyl ketone (d) Allyl methyl ketone

Sketch the hydrogen bonding between benzaldehyde and water.

Chloral is one of the common names for trichloroethanal. Its hydrate has featured prominently in countless detective stories as the notorious “Mickey Finn” knockout drops. Write a structural formula for chloral hydrate.

Cyanohydrin formation is reversible in base. Using sodium hydroxide as the base, use curved arrows to show the elimination of HCN from the cyanohydrin product in the presence of sodium hydroxide in step 2 in Mechanism 18.3.

Methacrylonitrile is an industrial chemical used in the production of plastics and fibers. One method for its preparation is the acid-catalyzed dehydration of acetone cyanohydrin. Deduce the structure of methacrylonitrile.

Be sure you fully understand Mechanism 18.4 by writing equations for steps 1–3. Use curved arrows to show electron flow.

Write the structures of the cyclic acetal or ketal derived from each of the following. (a) Cyclohexanone and ethylene glycol (b) Benzaldehyde and 1,3-propanediol (c) Isobutyl methyl ketone and ethylene glycol (d) Isobutyl methyl ketone and 2,2-dimethyl-1,3-propanediol

Problem 18.10 asked you to write details of the mechanism describing formation of benzaldehyde diethyl acetal from benzaldehyde and ethanol. Write a stepwise mechanism for the acid hydrolysis of this acetal.

What other combination of ylide and aldehyde or ketone will give methylenecyclohexane by a Wittig reaction? Write a balanced equation for the reaction.

(a) The product expected from nucleophilic addition of an ylide to an aldehyde or ketone belongs to a class of substances called betaines. Like ylides, betaines contain a positively charged and a negatively charged atom and both have an octet of electrons; they differ from ylides in that the two charged atoms are nonadjacent. Write a structural formula for the betaine corresponding to nucleophilic addition of methylenetriphenylphosphorane to cyclohexanone. (b) Use curved arrows to show the conversion of the betaine in (a) to an oxaphosphetane. (c) Use curved arrows to show the one-step conversion of the betaine in (a) to methylenecyclohexane and triphenylphosphine oxide.

What is the relationship between the major and minor products of the reaction just described? Are they enantiomers or diastereomers?

Each of the following aldehydes or ketones is known by a common name. Its substitutive IUPAC name is provided in parentheses. Write a structural formula for each one. (a) Chloral (2,2,2-trichloroethanal) (b) Pivaldehyde (2,2-dimethylpropanal) (c) Acrolein (2-propenal) (d) Crotonaldehyde [(E)-2-butenal] (e) Citral [(E)-3,7-dimethyl-2,6-octadienal] (f) Diacetone alcohol (4-hydroxy-4-methyl-2-pentanone) (g) Carvone (5-isopropenyl-2-methyl-2-cyclohexenone) (h) Biacetyl (2,3-butanedione)

Repeat the preceding problem for cyclopentanone instead of propanal.