Predict the major products of the following reactions, including stereochemistry where appropriate. (k) cyclopentanol + H 2 SO 4 /heat (l) product from (k) + OsO 4 /H 2 O 2 , then HIO 4 (m) sodium ethoxide + 1-bromobutane

Welcome back, everyone. Draw the products of each of the following. We have a three part problem. And the first part of the problem states that the starting material is cyclops tool. So we want to draw a seven member ring and specifically we want to add an alcohol group to one of our carbons. Oh And the problem states that we are producing a reaction with sulfuric acid in the presence of heat. And we have to understand that this reaction is an acid catalyzed dehydration of alcohols in an acid catalyzed dehydration of alcohols. We have to recall that we want to form the seeds of product or the more substituted alkin by removing one of our beta hydrogens that are equivalent, right? If they are equivalent due to the line of symmetry, that means we can only produce one possible L king. The net result is the removal of the alcohol group, the removal of beta hygen and the placement of a double bond moving on to the second reaction. It says that we're using the product from reaction one. And now we are performing multiple reactions. First of all, we're adding osmium to trim, followed by peroxide. And we have to know that this is a sin di hydroxylation in which the net result of the reaction is the removal of the pi bond in the formation of a viscal dial. Let's not worry about the configuration. We know it's an addition, but we're not asked to show the stereo chemistry. And then the next step, we're adding hio four meta perio acid. Let's recall that this is an oxidative cleavage of Visy dials. The net result of this reaction is simply the cleavage of the carbon carbon bond. And then each alcohol group becomes a corresponding carbonel group. Since we have to implicit hydrogens, those would be two aldehyde groups formed. How do we draw it? Well, essentially, let's just break the carbon carbon bond. We understand that we are going to get 1234567 number chain with the aldehyde groups at carbons one and six. So one of them, right, let's go ahead and for five more carbons, 12, we or five and now the sixth one, which essentially becomes another aldehyde group. So that's our next product. Let's count the number of carbon atoms. We want to have 1234567. So actually, we're missing an additional carbon atom. Let's fix that 1234567, well done. And now we're just going to add that we sultan held the Heide group well done. Now, we have our products for number two. And for number three, it says that we are performing a reaction between potassium meth oxide. Potassium is an iron spectator. So we can just use meth ide and met oxide reacts with one chloral propane. So we want to draw a three member chain, the chloral group is bonded to carbon. Number one. So we have a strong Nile and a primary substrate. This is a simple essence to substitution or reaction. We are forming an ether. A three member chain gets von the oxygen that is von see the metal group and that's it. Let's label our final products. For number one, that's an LK. For number two, we have an aldehyde and for number three, we have formed an ether. Thank you for watching.

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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
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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

10. Addition Reactions

Dihydroxylation

Organic Chemistry

10. Addition Reactions

Dihydroxylation

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6:11 minutes

Problem 39k,l,m

Textbook Question

Predict the major products of the following reactions, including stereochemistry where appropriate.
(k) cyclopentanol + H₂SO₄/heat
(l) product from (k) + OsO₄/H₂O₂, then HIO₄
(m) sodium ethoxide + 1-bromobutane

Verified step by step guidance

Step 1: For reaction (k), cyclopentanol reacts with H2SO4 and heat. This is an acid-catalyzed dehydration reaction. The hydroxyl group (-OH) is protonated by H2SO4, forming water as a leaving group. The cyclopentanol undergoes elimination to form cyclopentene as the major product. Ensure to consider the formation of the double bond and stereochemistry if applicable.

Step 2: For reaction (l), the product from (k), cyclopentene, reacts with OsO4 and H2O2. This is a dihydroxylation reaction, where OsO4 adds two hydroxyl groups (-OH) to the double bond in a syn addition manner, forming a cis-1,2-diol. Then, HIO4 cleaves the diol via oxidative cleavage, breaking the C-C bond between the hydroxyl groups and forming aldehydes or ketones as products. Carefully analyze the structure to predict the cleavage products.

Step 3: For reaction (m), sodium ethoxide (NaOEt) reacts with 1-bromobutane. This is an example of an SN2 reaction mechanism, where the nucleophile (ethoxide ion, CH3CH2O⁻) attacks the electrophilic carbon attached to the bromine atom in 1-bromobutane. Bromine leaves as a leaving group, and the ethoxide ion replaces it, forming ethylbutane. Consider the stereochemistry of the SN2 reaction, which involves inversion of configuration at the carbon center.

Step 4: Review the stereochemistry for each reaction. For (k), the stereochemistry of the double bond in cyclopentene is not relevant as it is a planar molecule. For (l), ensure the syn addition of hydroxyl groups during dihydroxylation and the cleavage products from HIO4. For (m), confirm the inversion of configuration due to the SN2 mechanism.

Step 5: Summarize the major products for each reaction: (k) cyclopentene, (l) aldehydes/ketones from oxidative cleavage, and (m) ethylbutane. Ensure to verify the reaction mechanisms and stereochemical outcomes for accuracy.

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Key Concepts

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

Acid-Catalyzed Dehydration

In the presence of an acid like H2SO4, alcohols can undergo dehydration to form alkenes. This reaction involves the protonation of the alcohol, leading to the formation of a carbocation, which can then lose a water molecule. The stability of the carbocation and the possibility of rearrangements are crucial for predicting the major product and its stereochemistry.

Dihydroxylation and Cleavage Reactions

The reaction of alkenes with OsO4 followed by H2O2 leads to syn-dihydroxylation, adding hydroxyl groups across the double bond. Subsequent treatment with HIO4 cleaves the resulting diol, producing carbonyl compounds. Understanding the stereochemistry of the initial dihydroxylation is essential for predicting the final products after cleavage.

Williamson Ether Synthesis

The reaction between sodium ethoxide and 1-bromobutane exemplifies the Williamson ether synthesis, where an alkoxide ion acts as a nucleophile to attack a primary alkyl halide. This reaction typically proceeds via an SN2 mechanism, leading to the formation of an ether. Recognizing the mechanism and the nature of the reactants is vital for predicting the product structure.

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