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29 Cards in this Set
- Front
- Back
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Why are the hydroxyl hydrogens of phenols more acidic than those of alcohols?
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B/c of resonance structures that distribute the negative charge throughout the ring, thus stabilizing the anion.
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A phenol will have a higher/lower Ka than a straight chained alcohol.
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Higher Ka, smaller pKa.
Strong acids have high Ka's and small pKa's. |
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Electron withdrawing groups increase/decrease acidity.
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Increase. They stabilize the anion, making the alcohol more acidic.
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Electron donating groups increase/decrease acidity.
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Decrease.
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1' ROH are mildly oxidized to...
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Aldehydes
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2' ROH are mildly oxidized to ....
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Ketones
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1' ROH are strongly oxidized to ....
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Carboxylic acids
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Carboxylic acids are mildly reduced to...
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Aldehydes
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Carboxylic acids are strongly reduced to ...
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1' Alcohols
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Ketones are reduced to ...
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2' Alcohols
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What are the 2 most frequently used reducing reagents?
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1. NaBH4 - more selective, easier to handle
2. LAH - more powerful and difficult to work with |
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Phenols can be synthesized via hydrolysis of ...
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diazonium salts
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Alcohols can be dehydrated in a stongly acidic solution to produce alkenes. The mechanism of this dehydration is E1/E2 SN1/SN2.
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E1 and proceeds via the protonated alcohol. Major product is the more substituted.
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Protonating an alcohol makes water the leaving group, which is good for SN1 reactions, even better, the alcohol can be converted to ______ which is good for SN2 rxns.
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Tosylate aka p-toluenesulfonate
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PCC role in reactions
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mild oxidant
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KMnO4 role in reactions
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strong oxidant
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Na2Cr2O7 role in reactions
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strong oxidant
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What is a Jones Reagent?
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CrO3, H2SO4 in acetone
very strong oxidant |
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What oxidizes 1' ROH to COOH and 2' ROH to RCOR?
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Jones Reagent
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Treatment of phenols with oxidizing agents produces...
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quinones
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Ethers are __________ polar and therefore ____________ soluble in water.
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Slightly/slightly
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Williamson Ether synthesis creates ethers from ...
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the reaction of metal alkoxides with 1' alkyl halides or tosylates
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Williamson Ether synthesis proceeds via E1/E2 SN1/SN2
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SN2. Alkoxides only attack nonhindered halides. Thus to synthesize a methyl ether, an alkoxide must attack a methyl halide; not the other way around (too hindered).
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Oxidation of an alkene with a peroxy acid such as mcpba produces...
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Oxirane
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Which of the following reagents should be used to convert CH3(CH2)3CH2OH into CH3(CH2)3CHO?
a. KMnO4 b. Jone's reagent c. PCC d. LAH |
C. The best way to prepare RCOH from 1' ROH is to use PCC. KMnO4 is a strong oxidizing agent and converts a 1' to a COOH. Jone's reagent is a very strong oxidizer. LAH is a reducing agent, and will not oxidize an alcohol.
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Since epoxides are highly strained cyclic ethers, they are susceptible to cleavage via E1/E2 SN1/SN2 reactions.
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SN2. Can be acid or base catalyzed.
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Epoxide cleavage can be acid or base catalyzed. The most substituted carbon is attacked in the presence of an....
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Acid
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Epoxide cleavage can be acid or base catalyzed. The least substituted carbon is attacked in the presence of an....
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Base. Base catalyzed cleavage has the most SN2 character, so it occurs at the least hindered carbon.
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Tertiary ROH's are oxidized with difficulty because
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There is no hydrogen attached to the carbon with the hydroxyl group.
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