Give two syntheses for (CH 3 ) 2 CH—O—CH 2 CH 3 , and explain which synthesis is better.

Welcome back everyone for this problem we arrest to give to synthetic approaches to this compound employing an essence to reaction and also discuss which approach is better. This structure is to metal to propose see propane and after careful analysis we noticed that there is the central oxygen atom with two L kill groups. On the left we have the third beetle group, and on the right we have a purple group to al kiel groups, bonnets and auction adam makes an ether. So we are synthesizing an ether. And one of the classical ways to synthesize an ether is the Williamson ether synthesis. Now, even if you're not familiar with this reaction, that's fine and don't worry, it's just sufficient to understand that we're dealing with an SN two reaction and Williamson ether synthesis is indeed an essence a reaction that is very common in either synthesis. So it's just sufficient to understand that if you recall the principles of an essence a reaction, you'll be good. Now let's recall the principles of an essence a reaction. Any essence a reaction needs two things at least a strong new profile or a negatively charged new profile and also ideally a primary or a secondary substrate. What we can also add a good leading group. Now looking at a if we need a strong nuclear file, one of the classical strong nuclear files is oxygen with a negative charge and indeed we have a source of oxygen in our original structure. So we can try to break the carbon oxygen bond this way or another way to separate oxygen from the remaining part of the original molecule. If we look at the first pathway where we have bond cleavage, we produce two fragments, One of them is the third Beatle group with prop oxen. And looking at the cleavage of the blue bond, we form beat oxide and the profile group. Now we are happy to see that we have a strong nuclear file in each case notice that there is negatively charged oxygen and negatively charged oxygen means a strong nuclear. How meaning out of two remaining fragments we wish to produce a good substrate for us and to produce a good substrate. We essentially just want to add a good leaving group for the first fragment. For the third visa group we might choose a good living group such as a high um high mass or a bigger size halogen such as bromine or iodine. So we may add room in here and similarly for the appropriate group. We may also choose that exactly same romaine for our synthesis because it's a very good leaving group for us. This might correspond to our synthesis. All that we have to do. Now is simply to check whether these reactions make sense. Give these to our our nuclear files And for the reaction in red we will simply look at the mechanism of an essence reaction. The negatively charged nuclear file will attack the electra Felix center of the substrate and simultaneously we will have the loss of the leaving group forming our final structure. In this case, I'm a first world draw my nuclear file And then it is now bonded to the 3rd Beatle Group, which is indeed the original substrate. Similarly, if you look at the second pathway and if you look at this mechanism, the negatively charged oxygen will attack the electra Felix center and simultaneously the leaving group belief I gained may starve with my nuclear file oxygen, third Beatle group and then I have a problem group over here and this again is my original compound. That means the two pathways that we have proposed are perfectly fine and we're happy to see them. They are both suitable just as requested. We have these two pathways and those are our final answers. The only thing we want to discuss which one of the two is better. And to do this, simply recall the principles of an essence a reaction. And what kind of substrates do we wish to see in our essence reactions. If we go back in part B of our analysis was said that ideally we want to have either a primary or a secondary substrate for an SN two reaction. Because tertiary substrates are are extremely useful in SN one reactions, but not preferred in SN two reactions. That said, if you look at the nature of our substrates, the first one is a territory substrate because the electra Felix center has three neighboring carbon atoms and the second one is primary because the electra Felix center only has one neighboring carbon atom, and because primary substrates are best for SN two reactions, followed by secondary ones for by tertiary ones. The second pathway in blue is preferred for this reaction, and we can say that yes, it is better. The correct answer for this. Multiple choice question is C. And in case you have any questions, feel free to leave them down below. Thank you for watching this video.

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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
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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
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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
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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

7. Substitution Reactions

SN2 Reaction

Organic Chemistry

7. Substitution Reactions

SN2 Reaction

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Problem 36

Textbook Question

Give two syntheses for (CH₃)₂CH—O—CH₂CH₃, and explain which synthesis is better.

Verified step by step guidance

Step 1: Analyze the target molecule (CH3)2CH—O—CH2CH3. It is an ether, which can be synthesized using the Williamson ether synthesis. This method involves reacting an alkoxide ion with a primary alkyl halide.

Step 2: First synthesis approach: Use isopropanol ((CH3)2CH—OH) to form the isopropoxide ion by deprotonating it with a strong base like NaH or K. Then react the isopropoxide ion with ethyl bromide (CH3CH2Br) to form the desired ether.

Step 3: Second synthesis approach: Use ethanol (CH3CH2—OH) to form the ethoxide ion by deprotonating it with a strong base like NaH or K. Then react the ethoxide ion with isopropyl bromide ((CH3)2CH—Br) to form the desired ether.

Step 4: Compare the two syntheses: The Williamson ether synthesis works best when the alkyl halide is primary because secondary and tertiary alkyl halides are prone to elimination reactions under basic conditions. Therefore, the first synthesis (using ethyl bromide as the alkyl halide) is better because ethyl bromide is a primary alkyl halide, minimizing side reactions.

Step 5: Conclude: The first synthesis is preferred due to the reduced likelihood of elimination reactions and higher yield of the desired ether. The second synthesis may lead to side reactions due to the secondary nature of isopropyl bromide.

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Key Concepts

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

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule by a nucleophile. In the context of the question, the synthesis of (CH3)2CH—O—CH2CH3 can occur through either an SN1 or SN2 mechanism, depending on the structure of the reactants and the conditions. Understanding the nature of the nucleophile and the substrate is crucial for predicting the reaction pathway.

SN2 Mechanism

The SN2 mechanism is a one-step nucleophilic substitution process where the nucleophile attacks the electrophile simultaneously as the leaving group departs. This mechanism is characterized by a backside attack, leading to inversion of configuration at the carbon center. It is favored in primary and some secondary substrates, making it a potential pathway for synthesizing (CH3)2CH—O—CH2CH3.

Reaction Conditions and Selectivity

The choice of reaction conditions, such as solvent, temperature, and concentration, significantly influences the outcome of nucleophilic substitution reactions. For example, polar aprotic solvents favor SN2 reactions by stabilizing the nucleophile without solvating it too much. Evaluating the conditions for each proposed synthesis will help determine which method is more efficient and yields a higher purity of the desired product.

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