1) NaNH 2 2) CH 3 Br 3) H 2 /Lindlar's catalyst

All right, guys. So in terms of alkenide retrosynthesis, it really isn't going to get easier than this. My first step was that we needed to make this a nucleophile. Right now, triple bond is not a nucleophile unless it gets deprotonated. So my first step, what I want to use is just some kind of strong base like NaNH2. Okay? What that's going to do in my first step is it's going to deprotonate my alkyne to turn into an alkynine. Okay? Because there's an H here that gets deprotonated by the NH two negative that pulls it off. Now I've got that triple bond. Now you guys should know what do I react that triple bond with or that alkynide with to add one more carbon. I should react it with an alkyl halide that has one carbon on it because alkyl halides are the electrophiles. So I should react it with CH3X. You pick the halogen. In this case, I'm going to pick br. But you could have picked I, you could have picked cl. F not so much. F isn't as good of a leaving group. So now I'm going to go ahead and write this here. Let me even draw it out a little bit better so you could see. This is going to be a backside attack. According to my flowchart, negatively charged nucleophile, methyl alkyl halide. That's a methyl. So this is going to do SN2 for sure. So I would get my back side attack. And what I wind up getting at the end of this is a triple bond that looks like this. Cool. Right? So now I have the right number of carbons. Notice that now I have 4 plus, of course, I have br negative. Who cares about that? That's just going to be a leaving group. So now it turns out that I can go from this to this in one step. What reagent is that going to be? So I told you guys we need to know how to make the alkanides, which we did. We made the negative charge. We need to know how to react it, which we just did. And we need to know how to transform it afterwards. The way we transform it is through hydrogenation reactions. So in this case, we would hydrogenate it with H2 over Lindlar's. Why? Because this is a cis double bond. Make sense? And that's it. That's our end product. So see that wasn't so bad, but you just have to get used to this idea of working kind of working backwards and thinking what do I need to do to make it look more like that. Okay? So does that make sense so far? Now go ahead and try to do this next one. What you're going to notice about this next one is that it's already getting worse because in the first one, I was easy on you guys. I just gave you a triple bond right there. Now, I'm giving you a double bond. Double bonds don't react the same way as triple bonds. So you're going to need to figure out what to do with that in order to make it look like this. All right? So go ahead and try your hardest to get this one right.

1) NaNH 2 2) CH 3 Br 3) H 2 /Lindlar's catalyst

1) H 2 /Lindlar's Catalyst 2) KMnO 4 , OH - , Δ / H + 3) NaBH 4 4) CH 3 MgBr

1) O 3 , Me 2 S 2) EtLi / H 3 O + 3) LDA

Table of contents

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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
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

14. Synthetic Techniques

Alkynide Alkylation

Organic Chemistry

14. Synthetic Techniques

Alkynide Alkylation

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Multiple Choice

Propose a synthesis:

1) H₂/Lindlar's Catalyst
2) KMnO₄, OH^-, Δ / H⁺
3) NaBH₄
4) CH₃MgBr

1) LiAlH
2) CH₃Cl
3) H₂/Pt

1) NaNH₂
2) CH₃Br
3) H₂/Lindlar's catalyst

1) O₃, Me₂S
2) EtLi / H₃O⁺
3) LDA

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Verified step by step guidance

Identify the starting material and the target molecule. The starting material is an alkyne (ethyne) and the target molecule is a cyclopropene.

Recognize that the transformation involves converting a linear alkyne into a cyclic alkene, specifically a cyclopropene.

Consider the use of a strong base like NaNH2 to deprotonate the terminal alkyne, generating an acetylide ion.

Plan to perform a nucleophilic substitution reaction with an alkyl halide, such as CH3Br, to form a new carbon-carbon bond, extending the carbon chain.

Use a selective hydrogenation process, such as H2 with Lindlar's catalyst, to partially reduce the alkyne to a cis-alkene, which can then undergo cyclization to form the cyclopropene.