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Org 1 Review - Reactions of Alcohols

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nudafizo's version from 2017-02-20 23:36

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Question Answer
What is OTs? Why is it useful? OTs = tosyl (para-methyltoluenesulfonate). It's a great leaving group. One of the most useful ways to make an alcohol (HO) into a good leaving group is to add TsCl to it to make the tosylate (OTs).
What is a Grignard reagent?A grignard reagent has the general form RMgX where R is an alkyl or alkenyl group, Mg is magnesium and X is a halide. They are strong nucleophiles and add to electrophiles like aldehydes, ketones, and esters.
Give a way of converting an alcohol to a good leaving group that never affects the stereochemistry of the alcoholTurn it into the tosylate - this simply involves replacement of H with Ts without nucleophilic attack at the carbon of the alcohol.
What are some methods of converting an alcohol into a good leaving group that go through an SN2 at the alcohol carbon?a) PBr3 b) SOCl2 c) POCl3 as well as similar compounds. If the alcohol is on a stereocenter, the new halide will form with inversion.
How does one form a Grignard reagent? treat an alkyl halide with magnesium metal (Mg) in an ether solvent such as diethyl ether (Et2O).
What is the product when a ketone is treated with K2Cr2O7 ? no reaction, ketones cannot be oxidized further to carboxylic acids.
Is the conversion of an aldehyde to a carboxylic acid an oxidation or reduction? it's an oxidation (net removal of H2)
Give an example of a reagent that will convert an alcohol to a carboxylic acid? KMnO4 will do this, as well as K2Cr2O7 and similar reagents involving chromium (e.g. CrO3 + H2SO4) the only exception being PCC, which will stop at the aldehyde.
Give an example of a reagent that will convert an aldehyde to an alcohol? Sodium borohydride (NaBH4) will do this, as well as LiAlH4. (Lithium aluminum hydride)
The conjugate base of an alcohol is called an ______ Alkoxide
How are ethers cleaved to alcohols? Strong acids (e.g. hydroiodic acid, HI) will perform this reaction.
Is the conversion of an alcohol to an aldehyde or ketone an oxidation or a reduction?it's an oxidation (net removal of H2)
Is the conversion of a carboxylic acid to an alcohol an oxidation or a reduction?it's a reduction (net removal of two equivalents of H2)
Name 2 ways of making a hydroxyl group into a good leaving group: 1) add acid, which will turn OH into OH2(+), which is a much better leaving group [seen in the E1 reaction). 2) convert the OH into OTs by using TsCl, which is a much better leaving group. A third method would be to convert it to an alkyl halide through SOCl2 or similar reagent.
What are two useful reactions for the synthesis of ethers? Two useful reactions: 1) SN2 of an alcohol with an alkyl halide (this is the Williamson synthesis of ethers) 2) oxymercuration of an alkene with alcohol as solvent
Why do we write "acid workup" after a Grignard reaction? Acid workup is to protonate the negatively charged oxygen we get after the Grignard reaction.
What is "oxidation" (3 definitions) Oxidation: loss of H2, gain of O, or loss of electron(s)
What is "reduction" 3 definitions Reduction: gain of H2, loss of O, or gain of electron(s)
What are two different ways to make alkyl bromides from alcohols in one step? a) PBr3 b) SOBr2
How do you reduce a carboxylic acid to an alcohol? Use LiAlH4
Which is more reactive, NaBH4 or LiAlH4?LiAlH4 is considerably more reactive - it is powerful enough to reduce carboxylic acids and esters to alcohols, whereas NaBH4 will not reduce these groups to alcohols.
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Org 1 Review - Thermodynamics
Org 1 Review - Free Radicals
Org 1 Review - Reactions of Alcohols
Org 1 Review - Alkynes
Org 1 Review - Substitution and Elimination
Org 1 Review - Reactions of Double Bonds
Org 1 Review - Stereochemistry
Org 1 Review - Conformations
Org 1 Review - Structure and Bonding