All Questions
Tagged with synthesis stereochemistry
11
questions
6
votes
1
answer
5k
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Why does only the cis-isomer of potassium dioxalatodiaquochromate(III) form?
A friend of mine performed a standard synthesis reaction of potassium dioxalatodiaquochromate(III) by adding potassium dichromate to ethandioic acid dihydrate and a little water. The synthesis ...
- 173
6
votes
1
answer
3k
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Synthesis of an epoxide from 1,2-diol
Why is there no formation of epoxide when the two OH-groups are on different planes? I do understand the epoxidation mechanism. However, I would be grateful if someone cleared the specific ...
- 109
0
votes
2
answers
159
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What is the mechanism of the reaction of ethyl prop-2-ynoate to ethyl (2Z)-2,3-dibromoprop-2-enoate?
It's really weird for the product is 99％ Z-comformation?
Please tell me why?
This reaction can be found in scifinder.
0
votes
1
answer
865
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Stereochemistry of Gabriel Synthesis
I read that the primary amine product of Gabriel Synthesis is a racemic mixture. However, when analyzing the reaction the stereochemical step(s) are all $S_N2$. Thus, I figured if you are careful you ...
- 807
4
votes
1
answer
2k
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How to get (2R,3R)-2,3-dibromobutane from but-2-yne?
What I had in mind was to form but-2-ene with $\ce{H2}$ and Lindlar's catalyst and then simply add bromine ($\ce{Br2}$). But this addition, if I'm not mistaken, is a trans-addition. So I would end up ...
- 453
1
vote
1
answer
3k
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How to determine which reagent to use H2; lindlar catalyst vs Na;NH3(l)?
I do understand that H2; Lindlar will give a cis double bond and Na;NH3(l) will give trans double bond. However, I am having difficulty understand how to determine which reagent will work in this ...
6
votes
1
answer
472
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Diastereoselectivity in synthesis problem (4 stereocenters)
Why is the particular diastereomer the major product of the sequence starting from racemic enone? I know that hydroboration is syn, therefore the arrangement of ring junction H atom and OH group. Why ...
- 14.4k
4
votes
1
answer
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In the Wittig reaction, why do stabilised ylides produce E-alkenes and unstabilised ylides produce Z-alkenes? [duplicate]
Wikipedia says that with unstabilised ylides they react very quickly in step 1-2 and step 4-5 is the rate limiting step. But with stabilised ylides step 1-2 is the rate limiting step and this is why ...
- 491
9
votes
1
answer
628
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Stereochemistry of epoxide hydrolysis under acidic conditions
The epoxide on the top of the picture, in aqueous acid hydrolyzes to the compound below. What is the mechanism of this reaction? Standard epoxide opening in acidic conditions would happen at the more ...
- 14.4k
5
votes
2
answers
10k
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How do you change the cis-trans isomerism of compounds?
I would like to know a general procedure for the synthesising cis isomers from their trans counterparts and vice versa.
- 2,461
12
votes
2
answers
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Is it possible, chemically, to change a dextrorotatory compound to its levorotatory counterpart?
Is it possible, chemically, to change a dextrorotatory compound to its levorotatory counterpart? E.g., is it possible to change dextrodopa to levodopa?
- 2,461