The complete, detailed mechanism for a given reaction is to be drawn, and the major product is to be predicted. Concept introduction: Intramolecular reactions are the ones in which the electron-rich and electron-poor sites are present within the same molecule. When ketones or aldehydes are treated with a strong base, they yield β -hydroxycarbonyl compounds via an aldol addition. Under these basic conditions, an enolate anion acts as a nucleophile. An intramolecular reaction is favored when it forms a five or six-membered ring. Intramolecular reactions involving the attack of an aldehyde C=O are favored over ones involving the attack of a ketone C=O . The first step is the formation of an enolate ion. The HO − reversibly deprotonates the alpha carbon to yield an enolate anion. In step two, the newly formed enolate anion, which serves as a nucleophile, attacks the carbonyl carbon present within the same molecule. The product of this step is an alkoxide ion, which is subsequently protonated in step 3. The nucleophilic addition reaction to a ketone is generally less favorable than the addition to an aldehyde because in a ketone, there are two alkyl groups attached to the carbonyl carbon, but in an aldehyde, only one alkyl group is attached. The electron-donating effects from a ketone’s alkyl groups diminish the concentration of positive charge on the carbonyl carbon, making it less susceptible to the nucleophilic attack.

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Definition Definition Organic compounds that have a carbonyl group, C=O, as their functional group. The carbonyl group in aldehydes is placed at the end of the molecular structure, which means the C=O is attached to one hydrogen atom and an alkyl group or a benzene ring. Just like all the other homologous series in organic chemistry, the naming of aldehydes uses the suffix “-al”. The general molecular formula is C n H 2n O.

Chapter 18, Problem 18.32P

Interpretation Introduction

Interpretation:

The complete, detailed mechanism for a given reaction is to be drawn, and the major product is to be predicted.

Concept introduction:

Intramolecular reactions are the ones in which the electron-rich and electron-poor sites are present within the same molecule. When ketones or aldehydes are treated with a strong base, they yield β-hydroxycarbonyl compounds via an aldol addition. Under these basic conditions, an enolate anion acts as a nucleophile. An intramolecular reaction is favored when it forms a five or six-membered ring. Intramolecular reactions involving the attack of an aldehyde C=O are favored over ones involving the attack of a ketone C=O. The first step is the formation of an enolate ion. The HO− reversibly deprotonates the alpha carbon to yield an enolate anion. In step two, the newly formed enolate anion, which serves as a nucleophile, attacks the carbonyl carbon present within the same molecule. The product of this step is an alkoxide ion, which is subsequently protonated in step 3. The nucleophilic addition reaction to a ketone is generally less favorable than the addition to an aldehyde because in a ketone, there are two alkyl groups attached to the carbonyl carbon, but in an aldehyde, only one alkyl group is attached. The electron-donating effects from a ketone’s alkyl groups diminish the concentration of positive charge on the carbonyl carbon, making it less susceptible to the nucleophilic attack.

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(a 4 shows scanning electron microscope (SEM) images of extruded actions of packing bed for two capillary columns of different diameters, al 750 (bottom image) and b) 30-μm-i.d. Both columns are packed with the same stationary phase, spherical particles with 1-um diameter. A) When the columns were prepared, the figure shows that the column with the larger diameter has more packing irregularities. Explain this observation. B) Predict what affect this should have on band broadening and discuss your prediction using the van Deemter terms. C) Does this figure support your explanations in application question 33? Explain why or why not and make any changes in your answers in light of this figure. Figure 4 SEM images of sections of packed columns for a) 750 and b) 30-um-i.d. capillary columns.³

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Answer 2

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Definition Definition Organic compounds that have a carbonyl group, C=O, as their functional group. The carbonyl group in aldehydes is placed at the end of the molecular structure, which means the C=O is attached to one hydrogen atom and an alkyl group or a benzene ring. Just like all the other homologous series in organic chemistry, the naming of aldehydes uses the suffix “-al”. The general molecular formula is C n H 2n O.

Chapter 18, Problem 18.32P

Interpretation Introduction

Interpretation:

The complete, detailed mechanism for a given reaction is to be drawn, and the major product is to be predicted.

Concept introduction:

Intramolecular reactions are the ones in which the electron-rich and electron-poor sites are present within the same molecule. When ketones or aldehydes are treated with a strong base, they yield β-hydroxycarbonyl compounds via an aldol addition. Under these basic conditions, an enolate anion acts as a nucleophile. An intramolecular reaction is favored when it forms a five or six-membered ring. Intramolecular reactions involving the attack of an aldehyde C=O are favored over ones involving the attack of a ketone C=O. The first step is the formation of an enolate ion. The HO− reversibly deprotonates the alpha carbon to yield an enolate anion. In step two, the newly formed enolate anion, which serves as a nucleophile, attacks the carbonyl carbon present within the same molecule. The product of this step is an alkoxide ion, which is subsequently protonated in step 3. The nucleophilic addition reaction to a ketone is generally less favorable than the addition to an aldehyde because in a ketone, there are two alkyl groups attached to the carbonyl carbon, but in an aldehyde, only one alkyl group is attached. The electron-donating effects from a ketone’s alkyl groups diminish the concentration of positive charge on the carbonyl carbon, making it less susceptible to the nucleophilic attack.

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Answer 3

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Definition Definition Organic compounds that have a carbonyl group, C=O, as their functional group. The carbonyl group in aldehydes is placed at the end of the molecular structure, which means the C=O is attached to one hydrogen atom and an alkyl group or a benzene ring. Just like all the other homologous series in organic chemistry, the naming of aldehydes uses the suffix “-al”. The general molecular formula is C n H 2n O.

Chapter 18, Problem 18.32P

Interpretation Introduction

Interpretation:

The complete, detailed mechanism for a given reaction is to be drawn, and the major product is to be predicted.

Concept introduction:

Intramolecular reactions are the ones in which the electron-rich and electron-poor sites are present within the same molecule. When ketones or aldehydes are treated with a strong base, they yield β-hydroxycarbonyl compounds via an aldol addition. Under these basic conditions, an enolate anion acts as a nucleophile. An intramolecular reaction is favored when it forms a five or six-membered ring. Intramolecular reactions involving the attack of an aldehyde C=O are favored over ones involving the attack of a ketone C=O. The first step is the formation of an enolate ion. The HO− reversibly deprotonates the alpha carbon to yield an enolate anion. In step two, the newly formed enolate anion, which serves as a nucleophile, attacks the carbonyl carbon present within the same molecule. The product of this step is an alkoxide ion, which is subsequently protonated in step 3. The nucleophilic addition reaction to a ketone is generally less favorable than the addition to an aldehyde because in a ketone, there are two alkyl groups attached to the carbonyl carbon, but in an aldehyde, only one alkyl group is attached. The electron-donating effects from a ketone’s alkyl groups diminish the concentration of positive charge on the carbonyl carbon, making it less susceptible to the nucleophilic attack.

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Answer 4

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Definition Definition Organic compounds that have a carbonyl group, C=O, as their functional group. The carbonyl group in aldehydes is placed at the end of the molecular structure, which means the C=O is attached to one hydrogen atom and an alkyl group or a benzene ring. Just like all the other homologous series in organic chemistry, the naming of aldehydes uses the suffix “-al”. The general molecular formula is C n H 2n O.

Chapter 18, Problem 18.32P

Interpretation Introduction