ORGANIC - KLEIN 3E CH.12 - ALCOHOLS AND...

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ORGANIC - KLEIN 3E

CH.12 - ALCOHOLS AND PHENOLS

CONCEPT: ALCOHOL NOMENCLATURE

□ Glycols: Alcohols with two hydroxyls are called ___________; with three hydroxyls are called ____________

● Always give most priority to the –OH group.

EXAMPLE: Provide the correct common and IUPAC name of the following alcohols.

a.

b.

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CONCEPT: ACIDITY OF PHENOLS

Phenols are substantially more acidic than typical alcohols due to the _________________ effect.

● Recall, the more we can stabilize the conjugate base, the more acidic a compound will be.

Donating and Withdrawing Groups:

EXAMPLE: Predict which of the following would be the most acidic phenol.

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O,P-Directors vs. Meta-Directors

The __________ position has a much lessor effect on acidity than the _________ and __________ positions.

● This is due to the resonance structures that are able to be produced by different positions


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PRACTICE: Rank the following phenols in order of increasing acidity.

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CONCEPT: SYNTHESIS OF ALCOHOLS OVERVIEW

There are 4 different techniques commonly used to create alcohols in Organic 1. Thankfully, you already know all of them!

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CONCEPT: CONVERSION OF ALCOHOLS TO GOOD LEAVING GROUPS

□ Alcohols are terrible leaving groups. If we want to react with them, they need to be transformed.

●They can be converted into ____________ _________________ or ______________ _______________

2o and 3o Alcohols with HX: SN1 mechanism

1o alcohols with HX: SN2 mechanism

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□ SOCl2 and PBr3 are two of the most commonly used reagents to transform alcohols into alkyl halides

●They always proceed with __________________________ of configuration.

1o and 2o Alcohols to RX: SN2 mechanism

EXAMPLE: Determine the mechanism for the following reaction. Draw the final product.

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□ Alcohols can attack sulfonyl chlorides to create sulfonate esters.

●They always proceed with __________________________ of configuration.

Alcohols to Sulfonate Esters:

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Alcohol Conversion Summary:

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CONCEPT: INTRO TO REDOX

● Oxidation reactions involve an increase in the ______________ content of a molecule

● Reduction reactions involve an increase in the ______________ content of a molecule

EXAMPLE: Label the following transformations as oxidation or reduction.

a.

b.

c.

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CONCEPT: REDUCTION

□ Reducing agents are used to reduce molecules

● These reagents add hydrogens across π-bonds. Unsaturated hydrocarbons and carbonyls can be reduced.

General Mechanism: Nucleophilic addition of hydrogen

□ Reducing agents add to ALL π-bonds present. Multiple equivalents of hydrogen will react if possible.

● LiAlH4 is a strong reducing agent. It is able to reduce ANY carbonyl compound into alcohol

EXAMPLE: Draw the products of the following molecules reacted with LiAlH4

□ NaBH4 is a weak reducing agent. It can only add ____ equivalent of hydrogen and can only reduce CHO and ketones

EXAMPLE: Draw the products of the following molecules reacted with NaBH4

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PRACTICE: Predict the product of the following reactions

a.

b.

c.

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CONCEPT: OXIDATION

□ Oxidizing agents are used to oxidize molecules

● Most oxidizing agents add as much oxygen as possible while not breaking ANY C-C bonds.

EXAMPLE: Which of the following compounds could be oxidized?

□ These are called strong oxidizing agents. They include KMnO4 and the Cr6+ reagents (H2Cr2O4, CrO3, K2Cr2O7, etc.)

EXAMPLE: Draw the products of the previous molecules with a strong oxidizing agent

□ PCC is a weak oxidizing agent. It reacts similar but can only add ____ equivalent of oxygen to 1º alcohols.

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CONCEPT: OXIDATION MECHANISMS

□ One of the most popular oxidizing agents is the Jones Reagent.

● It can be generated through combination of a strong acid with a Cr6+ reagent.

Mechanism:

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PRACTICE: Predict the product of the following reactions

a.

b.

c.

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CONCEPT: WEAK OXIDATIVE CLEAVAGE

Ozonolysis: Ketones + Aldehydes + Formaldehyde

PRACTICE: Predict the products of the following reaction

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CONCEPT: NUCLEOPHILIC ADDITION

□ One of the most important ways that carbonyl compounds react is through nucleophilic addition.

● The carbonyl carbon is _____________________________

Nucleophilic Addition General Mechanism:

Nucleophilic Addition General Reactions:

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CONCEPT: PREPARATION OF ORGANOMETALLICS

□ Organometallics are alkylating agents that have mostly group IA or group IIA metals bonded to a carbon structure

● They can also react as strong ____________. Beware of cross-reactions with acidic hydrogens.

1. Sodium Alkynides

2. Grignard Reagents

3. Organolithium Reagents

4. Gilman Reagents

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CONCEPT: REACTIONS OF ORGANOMETALLICS

1. Substitution/Elimination on Alkyl Halides

2. Nucleophilic Addition on Ketones and Aldehydes

3. Nucleophilic Acyl Substitution on Esters

4. Base-Catalyzed Epoxide Ring Opening

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CONCEPT: USE OF PROTECTING GROUPS

□ Organometallics are powerful bases. They will react with any acidic protons available, ruining the reagent.

We can use tert-butyl or silyl ethers to protect alcohols from deprotonation by organometallic reagents

● p-Toluenesulfonic acid is an acid commonly used for this step (abbrev. TsOH or pTSA)

EXAMPLE: Provide the mechanism and final product for the following transformation

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PRACTICE: Predict the product of the following reaction.

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PRACTICE: Propose a synthesis to accomplish the following transformation.

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PRACTICE: Propose a synthesis to accomplish the following transformation (Hint: 4 steps)

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ORGANIC - KLEIN 3E CH.12 - ALCOHOLS AND...

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