Convergent syntheses are more efficient than linear syntheses because you risk less if one branch of your synthesis fails and because the same number of steps in a linear synthesis give a lower overall yield. For instance, in our synthesis we had three branches that converge to hexaphenylbenzene. We ran eight reactions. If the yield of each reaction was 90%, then our overall yield would be between 72 and 66 %, depending on which branch is limiting. On the other hand, if we had to do eight consecutive 90 % yield reactions, the overall yield would be 43% (0.98 x 100 %). Unfortunately it is not valid to calculate the overall yield on each branch of a convergent synthesis, only the overall yield of the branch of the limiting reagents. For instance if benzil and tetraphenylcyclopentadienone are the limiting reagents in their respective reactions, then we can only report the overall yield from benzaldehyde via benzoin. If dibenzyl ketone and tetraphenylcyclopentadienone are the limiting reagents then we can only report the overall yield from phenylacetic acid. And if diphenylacetylene is the limiting reagent then we could only report the overall yield from benzaldehyde (or benzyltriphenylphosphonium chloride if it is the limiting reagent) via stilbene. Use the following atomic weights to determine the limiting reagent branch of our synthesis. Then calculate the missing % yield(s) for that branch. Finally report the overall % yield from the starting reaction of that branch to hexaphenylbenzene. Give only 2 significant figures. If your final answer is a whole number, do not write a decimal. The grams next to an arrow are the grams of the compound previous to the arrow used in the reaction. The "grams made" are the grams of the product of that reaction. The % next to an arrow are the % yield of each respective reaction. This video through this link has further explanations of how to answer this question. C = 12, H = 1, O = 16 Answer: 85% O OH 64% 96 % + cr 56% Br 79%↓ OH 61%↓ 4.420 g 3.251 g↓ 5.172 g made 5.974 g 1.655 g↓ 4.320 g made

Convergent syntheses are more efficient than linear syntheses because you risk less if one branch of your synthesis fails and because the same number of steps in a linear synthesis give a lower overall yield. For instance, in our synthesis we had three branches that converge to hexaphenylbenzene. We ran eight reactions. If the yield of each reaction was 90%, then our overall yield would be between 72 and 66 %, depending on which branch is limiting. On the other hand, if we had to do eight consecutive 90 % yield reactions, the overall yield would be 43% (0.98 x 100 %). Unfortunately it is not valid to calculate the overall yield on each branch of a convergent synthesis, only the overall yield of the branch of the limiting reagents. For instance if benzil and tetraphenylcyclopentadienone are the limiting reagents in their respective reactions, then we can only report the overall yield from benzaldehyde via benzoin. If dibenzyl ketone and tetraphenylcyclopentadienone are the limiting reagents then we can only report the overall yield from phenylacetic acid. And if diphenylacetylene is the limiting reagent then we could only report the overall yield from benzaldehyde (or benzyltriphenylphosphonium chloride if it is the limiting reagent) via stilbene. Use the following atomic weights to determine the limiting reagent branch of our synthesis. Then calculate the missing % yield(s) for that branch. Finally report the overall % yield from the starting reaction of that branch to hexaphenylbenzene. Give only 2 significant figures. If your final answer is a whole number, do not write a decimal. The grams next to an arrow are the grams of the compound previous to the arrow used in the reaction. The "grams made" are the grams of the product of that reaction. The % next to an arrow are the % yield of each respective reaction. This video through this link has further explanations of how to answer this question. C = 12, H = 1, O = 16 Answer: 85% O OH 64% 96 % + cr 56% Br 79%↓ OH 61%↓ 4.420 g 3.251 g↓ 5.172 g made 5.974 g 1.655 g↓ 4.320 g made

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter16: Aldehydes And Ketones

Section: Chapter Questions

Problem 16.63P

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