Alcohols

Question 1

Substitution in Acidic Conditions: Primary Alcohols

Answer 1

Reactant: Primary Alcohol

Reagents: HBr, HI, or HCl (can be used with ZnCl₂) and heat

Product: Alkyl Halide

Mechanism: SN2

React Slower than tertiary and secondary

Stereochemistry: If it has a chiral center, it will have the inverted stereochemistry

Question 2

Substitution in Acidic Conditions: Secondary and Tertiary Alcohols

Answer 2

Reactants: Secondary or Tertiary Alcohol

Reagents: HBr, HI, HCl (can be used with ZnCl₂) and heat

Product: Alkyl Halide

Mechanism: SN1

Stereochemistry: If it has a chiral center, will have retained and inverted stereochemistry

Possibility of carbocation rearrangement

Question 3

Subsitiution in Basic Conditions

Answer 3

Reactants: Primary and Secondary Alcohols

Reagents: PCl₃, PBr₃, or SOCl₂ and pyridine

Products: Alkyl Halide

Mechanism: SN2

Stereochemistry: If there is a chiral center present, it will have the inverted stereochemistry

Question 4

Formation of a Sulfonate Ester

Answer 4

Reactants: Primary, Secondary, or Tertiary Alcohol

Reagents: SO2Cl-R (Can be the benzyl methyl seen or CH₃ or CF₃₎ and pyridine

Product: Sulfonate Ester

Mechanism: Look in Notes, but first step is a SN2 reaction on sulfur

Stereochemistry: Retained

Question 5

Reaction of Sulfonate Esters: Subsititution

Answer 5

Reactant: Sulfonate Ester friom a primary or secondary alchohol

Reagent: A good nucleophile

Product: will vary

Mechanism: SN2

Stereochemistry: If there is a chiral center, the stereochemistry is inverted

Question 6

Reaction of Sulfonate Esters: Eliminations

Answer 6

Reactant: Sulfonate Ester from a secondary or tertiary alcohol

Reagent: Strong base such as methoxy

Product: Alkene

Mechanism: E2

Question 7

Elimination in Acidic Conditions: Secondary and Tertiary Alcohols

Answer 7

Reactant: Secondary or Tertiary Alcohol

Reagent: H₂SO₄ and heat

Product: Alkene (Major: Trans or E, Minor: Cis or Z)

Mehchanism: E1

Can undergo carbocation rearrangement, and ring expansions

Question 8

Elimination in Acidic Conditions: Primary Alcohols

Answer 8

Reactant: Primary Alcohol

Reagent: H₂SO₄ and heat

Product: Alkene

Mechanism: E2 then E1

Question 9

Elimination in Basic Conditons

Answer 9

Reactant: Primary, Secondary, or Tertiary Alcohol

Reagents: POCl₃ and pyridine

Product: Alkene

Mechanism: E2

Question 10

Strong Oxidation: Primary Alcohols

Answer 10

Reactant: Primary Alcohol

Reagents: H₂CrO₄ or Na₂Cr₂O₇ and H₂SO₄

Product: Carboxylic Acid

Question 11

Mild Oxidation: Primary Alchohols

Answer 11

Reactant: Primary Alcohol

Reagents: *PCC and CH₂Cl₂

_*NaOCl and CH₃COOH in 0°C

*Swern oxidation: 1. ((CH₃)₂SO) dimethyl sulfoxide, ((COCl)₂) oxalyl chloride in -60°C 2. triethylamine ((CH₃CH₂)₃N)

Product: Aldehyde

Mehchanism by HOCl: Look in notes. uses SN2

Swern Oxidation: Look in notes, uses SN2 then E2

Question 12

Oxidation: Secondary Alchols

Answer 12

Reactant: Secondary Alcohol

Reagents:

*H₂CrO₄

*Na2Cr₂O₇ and H₂SO₄

_*PCC and CH₂Cl₂

*NaOCl and CH₃COOH in 0°C

*Swern oxidation: 1. ((CH3)₂SO) dimethyl sulfoxide, ((COCl)₂) oxalyl chloride in -60°C 2. triethylamine ((CH₃CH₂)₃N)

Mechanism:

Mehchanism by HOCl: Look in notes. uses SN2

Swern Oxidation: Look in notes, uses SN2 then E2

*

Question 13

Williamson Ether Synthesis

Answer 13

Reactant: Alcohol

Reagents:

1. NaH
2. Alkyl Halide

Product: Ether

You want the alcohol to be the bulkier side of the ether, and the alkyl halide to be the other side. If you have a benzene ring, you must turn it into phenol and deprotonate with NaOH, it can not be the alkyl halide because an aryl halide cannot undergo a SN2 reaction.

Question 14

Formation of a symmetrical ether

Answer 14

Reactant: Alcohol

Reagent: H₂SO₄ in heat

Product: Symmetrical Ether