Concept explainers
(a)
Interpretation: The given following compounds has to be prepared using an aldol addition in the first step.
Concept introduction: If two different carbonyl compound used in an aldol addition, known as a crossed-aldol reaction. If the two carbonyl compounds contain alpha carbon then four products are formed because two different enolate ion is formed.
If both carbonyl compounds have alpha hydrogens, primarily only one product is formed if LDA is used to remove the alpha hydrogen from carbonyl carbon that is needed for the enolate ion.
Because LDA is a strong base, all of the carbonyl carbon is converted to the enolate ion, so none of the carbonyl carbon is left behind to react with enolate ion. Therefore, the second carbonyl compound is added slowly.
(b)
Interpretation: The given following compounds has to be prepared using an aldol addition in the first step
Concept introduction: If two different carbonyl compound used in an aldol addition, known as a crossed-aldol reaction. If the two carbonyl compounds contain alpha carbon then four products are formed because two different enolate ion is formed.
If both carbonyl compounds have alpha hydrogens, primarily only one product is formed if LDA is used to remove the alpha hydrogen from carbonyl carbon that is needed for the enolate ion.
Because LDA is a strong base, all of the carbonyl carbon is converted to the enolate ion, so none of the carbonyl carbon is left behind to react with enolate ion. Therefore, the second carbonyl compound is added slowly.
(c)
Interpretation: The given following compounds has to be prepared using an aldol addition in the first step.
Concept introduction: If two different carbonyl compound used in an aldol addition, known as a crossed-aldol reaction. If the two carbonyl compounds contain alpha carbon then four products are formed because two different enolate ion is formed.
If both carbonyl compounds have alpha hydrogens, primarily only one product is formed if LDA is used to remove the alpha hydrogen from carbonyl carbon that is needed for the enolate ion.
Because LDA is a strong base, all of the carbonyl carbon is converted to the enolate ion, so none of the carbonyl carbon is left behind to react with enolate ion. Therefore, the second carbonyl compound is added slowly.
(d)
Interpretation: The given following compounds has to be prepared using an aldol addition in the first step.
Concept introduction: If two different carbonyl compound used in an aldol addition, known as a crossed-aldol reaction. If the two carbonyl compounds contain alpha carbon then four products are formed because two different enolate ion is formed.
If both carbonyl compounds have alpha hydrogens, primarily only one product is formed if LDA is used to remove the alpha hydrogen from carbonyl carbon that is needed for the enolate ion.
Because LDA is a strong base, all of the carbonyl carbon is converted to the enolate ion, so none of the carbonyl carbon is left behind to react with enolate ion. Therefore, the second carbonyl compound is added slowly.
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Chapter 17 Solutions
EBK ORGANIC CHEMISTRY
- Devise a concise synthesis for the following transformations. Clearly show the reagent and productfor each step. Each synthesis can be accomplished in two stepsarrow_forwardWhat reagents are required to carry out the following synthesis?arrow_forwardThe Stork reaction is a condensation reaction between an enamine donor and an α,β-unsaturated carbonyl acceptor. The overall reaction consists of a three-step sequence of formation of an enamine from a ketone, Michael addition to an α,β-unsaturated carbonyl compound, and hydrolysis of the enamine in dilute acid to regenerate the ketone. Consider the Stork reaction between acetophenone and 3-buten-2-one. Draw the structure of the product of the enamine formed between acetophenone and pyrrolidine. Draw the structure of the Michael addition product. Draw the structure of the final product.arrow_forward
- The Stork reaction is a condensation reaction between an enamine donor and an α,β-unsaturated carbonyl acceptor. The overall reaction consists of a three-step sequence of formation of an enamine from a ketone, Michael addition to an α,β-unsaturated carbonyl compound, and hydrolysis of the enamine in dilute acid to regenerate the ketone. Consider the Stork reaction between cyclohexanone and propenal Draw the structure of the product of the enamine formed between cyclohexanone and dimethylamine. - Michael addition to an α,β-unsaturated carbonyl compound, and - hydrolysis of the enamine in dilute acid to regenerate the ketone.arrow_forwardDevise a concise synthesis for the following transformations. Clearly show the reagent and productfor each step. Each synthesis can be accomplished in two stepsarrow_forwardPlease give the appropriate reagents to complete the following synthesis. 1 2 3arrow_forward
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- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning