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

10. Addition Reactions

Alkyne Halogenation

Organic Chemistry

10. Addition Reactions

Alkyne Halogenation

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3:27 minutes

Problem 45b

Textbook Question

What would the yield be if two more steps (each with an 80% yield) were added to the synthesis?

Verified step by step guidance

Step 1: Understand the concept of yield in a multi-step synthesis. The yield of a synthesis is calculated by multiplying the yields of each individual step. For example, if a synthesis has three steps with yields of 80%, 90%, and 70%, the overall yield is calculated as (0.8 × 0.9 × 0.7).

Step 2: Analyze the given synthesis. The image shows a three-step reaction sequence starting with acetylene (HC≡CH) and ending with 1,2-ethanediol (HOCH2CH2OH). Each step has a specific yield, and the problem asks about adding two more steps, each with an 80% yield.

Step 3: Assume the yield of the existing synthesis is known or calculated. If the yield of the current three-step synthesis is Y_current, the addition of two more steps with 80% yield each will modify the overall yield. The new yield can be calculated as Y_new = Y_current × (0.8 × 0.8).

Step 4: Multiply the yield of the existing synthesis by the yields of the additional steps. For example, if the current yield is 50%, the new yield would be calculated as 0.5 × 0.8 × 0.8.

Step 5: Ensure that the final yield is expressed as a percentage. After performing the multiplication, convert the decimal result back into a percentage by multiplying by 100. This gives the overall yield of the synthesis after adding the two steps.

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Key Concepts

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

Reaction Yield

Reaction yield refers to the amount of product obtained from a chemical reaction compared to the theoretical maximum amount possible. It is often expressed as a percentage, calculated by dividing the actual yield by the theoretical yield and multiplying by 100. Understanding yield is crucial for evaluating the efficiency of a synthesis process, especially when multiple steps are involved.

Sequential Reactions

In organic chemistry, sequential reactions involve a series of chemical transformations where the product of one reaction serves as the reactant for the next. Each step can have its own yield, which affects the overall yield of the final product. When calculating the total yield of a multi-step synthesis, the yields of each step must be multiplied together to determine the cumulative effect on the final product.

Lindlar's Catalyst

Lindlar's catalyst is a specific type of palladium catalyst that is used to selectively hydrogenate alkynes to cis-alkenes without further reducing them to alkanes. It is crucial in organic synthesis for controlling the degree of hydrogenation. Understanding its role helps in predicting the products of reactions involving alkynes and the subsequent steps in a synthesis pathway.

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