Chapter 11: Oxidation and Reduction Reactions

Oxidation

Loss of H, gain of O

Reduction

Gain of H, loss of O

Oxidation state

#valence electrons around carbon - # electrons belonging to carbon

Increase in oxidation state means oxidation occurs

The more pi bonds added

The more oxidized

Oxidation level

Number of bonds attached to heteroatoms

H2 and metal (hydrogenation)

Strong reducing agent

Adds H to each carbon (cis)

Makes N (from CN, N3, NO2) into NH2

H2 and Lindlar catalyst

Weak reducing agent

Adds an H to each carbon

O3 (ozonolysis)

Oxidation of rings

Has 2 five membered ring intermediates

Cleave pi bond and then oxidative or reductive work up

Reductive condition of ozonolysis

Strong reduction

DMS or Zn and H2O

Just add O to pi bond ends

Oxidative conditions of ozonolysis

Weak oxidation using H2O2

Add O to pi bond ends

Add O to adjacent H

OsO4 and tBuOH

strong Oxidizing agent

5 membered ring intermediate

Adds 2 OH (cis) to double bond

IO4

Oxidizing agent

Cleaves alkene same as ozonolysis under reductive workup

MCPBA

String oxidizing agent

Forms epoxide ring and breaks it

H3O Adds 2 OH (trans) to double bond

More substituted alkene reacts faster

Swern (COCl2 and DMSO)

Weak oxidation of alcohols

Removes an H from carbon and O, forming carbonyl

SWERVE THOSE CARBS

CrO and pyridine

Weak oxidizing agent of alcohols

PCC

Weak oxidizing agent of alcohols

CrO and Acid

Strong oxidizing agent of alcohols

MnO2

Weak oxidizing agent of benzyllic and allylic alcohols

KMnO4

Strong oxidizing agent

IBX and DMSO

Weak oxidizing agent of alcohols

Oxidation of alcohols

1° alcohol : aldehyde : carboxylic acid

2° alcohol : ketone

3° alcohol: NO REACTION

SnCl2

Reduces NO2 to NH2

Zn and acetic acid

Reduces NO2 to NH2

What is the only strong oxidizing reagent for alcohols?

CrO and acid, KMnO4

Strong money?

What are the only weak redox reagents for non alcohols?

LORI is weak even with non alcoholic drinks

Lindlar, Ozonolysis under Reductive conditions, IO4