Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

21. Aldehydes and Ketones: Nucleophilic Addition

Imine vs Enamine

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

Imine vs Enamine

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4:55 minutes

Problem 39h

Textbook Question

Predict the major products of the following reactions.
(h)

Verified step by step guidance

Step 1: Identify the reaction type. The given reaction involves a Wittig reagent (Ph₃P=CHR) and a ketone. This is a Wittig reaction, which is used to form alkenes by reacting a phosphonium ylide with a carbonyl compound.

Step 2: Analyze the reactants. The Wittig reagent contains a phosphonium ylide (Ph₃P=CH-CH=CH₂), and the ketone is acetone (CH₃COCH₃). The ylide will react with the carbonyl group of the ketone.

Step 3: Determine the mechanism. The Wittig reaction proceeds via nucleophilic attack of the ylide carbon on the carbonyl carbon, forming a betaine intermediate. This intermediate rearranges to form an oxaphosphetane, which then decomposes to yield the alkene product and triphenylphosphine oxide (Ph₃P=O).

Step 4: Predict the product. The alkene formed will result from the combination of the carbonyl carbon and the ylide carbon. The double bond will replace the oxygen atom of the ketone, and the substituents from both reactants will determine the structure of the alkene.

Step 5: Consider stereochemistry. Wittig reactions can produce E/Z isomers depending on the steric and electronic properties of the reactants. In this case, analyze the substituents to predict the major stereoisomer.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleophilic Addition

Nucleophilic addition is a fundamental reaction in organic chemistry where a nucleophile attacks an electrophilic carbon atom, typically in carbonyl compounds. This process results in the formation of a new bond, leading to the conversion of a carbonyl group (C=O) into an alcohol (C-OH) or other functional groups. Understanding this mechanism is crucial for predicting the products of reactions involving carbonyl compounds.

Imine Formation

Imine formation occurs when a primary amine reacts with a carbonyl compound, resulting in the creation of an imine (C=N) through a condensation reaction. This process involves the nucleophilic attack of the amine on the carbonyl carbon, followed by the elimination of water. Recognizing how imines can act as nucleophiles in subsequent reactions is essential for predicting the outcomes of reactions involving imines.

Reactivity of Ketones

Ketones are organic compounds characterized by a carbonyl group (C=O) flanked by two carbon atoms. Their reactivity is influenced by the presence of electron-donating or withdrawing groups, which can stabilize or destabilize the carbonyl carbon. Understanding the reactivity of ketones is vital for predicting how they will interact with nucleophiles, such as imines, in various organic reactions.

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Related Practice

Textbook Question

Show how you would accomplish the following synthetic conversions efficiently and in good yield. You may use any necessary additional reagents and solvents.

(d)

Textbook Question

Show how you would accomplish the following syntheses efficiently and in good yield. You may use any necessary reagents.

(b)

Textbook Question

Show how Wittig reactions might be used to synthesize the following compounds. In each case, start with an alkyl halide and a ketone or an aldehyde.

(a) Ph–CH=C(CH₃)₂

(b) Ph–C(CH₃)=CH₂

Textbook Question

Show how Wittig reactions might be used to synthesize the following compounds. In each case, start with an alkyl halide and a ketone or an aldehyde.

(d)

Textbook Question

(a) Outline the syntheses indicated in Solved Problem 18-2, beginning with aldehydes and alkyl halides.

(b) Both of these syntheses of 1-phenylbuta-1,3-diene form the central double bond. Show how you would synthesize this target molecule by forming the terminal double bond.

Textbook Question

Using cyclohexanone as the starting material, describe how each of the following compounds can be synthesized:

Textbook Question

Show how you would synthesize octanal from each compound. You may use any necessary reagents.

(f) octanoic acid

Textbook Question

Show how you would synthesize octanal from each compound. You may use any necessary reagents.

(g) ethyl octanoate

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