17791001
Description
Flashcards by John Rivada, updated more than 1 year ago
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Created by John Rivada
about 5 years ago
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| Question | Answer |
| What is tautomerism? |
Shift between two structure forms
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1 (binary/octet-stream)
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| What is enolate? | Deprotonated alcohol (OL) conjugated to alkene (ENE) |
| Is keto-enol tautomerism equilibrium or resonance? | Equilibrium because bonds between H and C/O are being made and broken |
| When you enolize a non-symmetrical ketone, which product is the thermodynamically stable one? | The one that results in the double bond with the most substituted ends |
| Which product is the thermodynamic one and which is the kinetic one when you enolize a non-symmetric ketone? | LDA and other hidnered amide bases deprotonate the less hindered site, resulting in the kinetic product Deprotonation at the more hindered site gives you the thermodynamic product |
| How do you enolize an ester? |
Use the O-R as the base because if it were to do carbonyl attack you get the starting material
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| Rate of enolization ease |
Same as nucleophilicity/basicity
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| How do you enolze an acid chloride | You don't Cl can act as a LG and give a ketene |
| How do you enolize carboxylic acid? |
In presence of base you just get deprotonation because carboxylic acid is more acidic
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3 (binary/octet-stream)
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| How do you enolze an amide? | 1° and 2°: No (pKa of proton on the N is much lower and you'll get a negative charged nitrogen) 3°: Noice! (since there's no protons to get deprotonated) |
| 'enolizable' imine and enamiens | ** |
| How do you enolize nitroalkanes and nitriles? |
Pretty easily
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4 (binary/octet-stream)
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| What helps make an enol thermodynamically stable? | Conjugation via dicarbonyls (e.g. dimedone) |
| Harp modification whatever | ** |
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5b (binary/octet-stream)
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https://www.youtube.com/watch?v=HgzGwKwLmgM
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5a (binary/octet-stream)
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| nitrosation of enols | ** |
| What are two kinds of stable enolate equivalents? | Lithium enolates and silyl enol ethers |
| Does enolation via lithium give kinetic or thermodynamic enolate? | kinetic |
| mechanism of lithium enolate | ** |
| mechanism of silyl enol ether formation | ** |
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What kind of electrophiles are compatible for this? Is this a hard or soft site?
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Hard
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6b (binary/octet-stream)
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| hydrolysis of enol ethers | ** |
| Slide 43 | ** |
| Slikde 44 | ** |
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