top of page

Organic Chemistry by Brown, Iverson, Anslyn, Foote | Mayya's Study Guide | Chapter 10

Chapter 10: Alcohols


Table of contents of main topics:


  • Nomenclature of Alcohols

  • Reaction of Alcohols with Active Metals

  • Conversion of Alcohols to Haloalkanes and Sulfonates

  • Acid-Catalyzed Dehydration of Alcohols

  • The Pinacol Rearrangement

  • Oxidation of Alcohols

  • Periodic Acid Oxidation of Glycols

  • Summary of Alcohol Reactions


Nomenclature of Alcohols

  1. Find the longest continuous carbon chain and start numbering from the end closest to the OH group. End the parent chain name with "ol" and put a number in front of the name signifying the carbon to which OH is attached.

  2. If the OH group is on a ring, start counting from the carbon that has the OH group.

  3. Proceed with naming substituted just like we did for alkanes and put the name together with substituents first (in alphabetical order) followed by the name of the parent.

  4. If there are multiple OH groups, use "diol" (2), and "triol"(3)...

  5. For molecules containing a double bond and an alcohol use parent name ending in "en"-#-"ol"


Alcohols can be classified as:

Primary = OH is on a carbon that is attached to one carbon only

Secondary = OH is on a carbon that is attached to two other carbons

Tertiary = OH is on a carbon attached to three more carbons


Reaction of Alcohols with Active Metals


Alcohols will get deprotonated when reacting with metals such as NaH.

Reaction of Alcohols with Active Metals
Reaction of Alcohols with Active Metals


Conversion of Alcohols to Haloalkanes and Sulfonates (How to make alcohol into a good leaving group).

Alcohols are very poor leaving groups. We oftentimes need to convert an alcohol into a good leaving group to do further reactions on the molecule. The reagents that make alcohol into a good leaving group are: HCl, HBr, HI, TsCl, PBr3 and SOCl2.


The reaction of alcohol with HBr or HCl yields Br or Cl instead of the OH group. Please note that these reactions are capable of rearrangements and do not always give the desired product.

Tertiary and secondary alcohols will reach with HX with Sn1, while primary alcohols with no extensive beta branching will undergo SN2.


Mechanism of the reaction of alcohol with HCl
Mechanism of the reaction of alcohol with HCl


The reaction of alcohol with TsCl (tosyl chloride) produces ROTs ( alkyl tosylate). OTs is an excellent leaving group. In this reaction, the stereochemistry of OH as it gets converted to OTS remains the same. For example, if OH was on a wedge, OTs would be on a wedge as well.


Preparation Of Sulfonate Esters Using sulfonyl chloride  (OH into OTs)
Preparation Of Sulfonate Esters Using sulfonyl chloride (OH into OTs)



PBr3 (phosphorus tribromide) turns OH into Br (works on most primary and secondary alkyl halides). Results in INVERSION of stereochemistry due to the SN2 reaction in the second step.


Reaction of alcohol with PBr3 and its mechanism
Reaction of alcohol with PBr3 and its mechanism

SOCl2 (thionyl chloride) with pyridine converts OH into Cl (also works on primary and secondary alcohols). It results in inversion of stereochemistry just like PBr3.


Reaction Of Alcohols With PBr3 and SOCl2
Reaction Of Alcohols With PBr3 and SOCl2

Acid-Catalyzed Dehydration of Alcohols

Alcohol can be reduced to an alkene via E1 elimination reaction. The reagent for the reaction is usually H2SO4/heat (sulfuric acid).


Making Alcohol Into An Alkene E1
Making Alcohol Into An Alkene E1

Mechanism for turning alcohol into an alkene.

The Pinacol Rearrangement

This is just another type of carbocation rearrangement.


The Pinacol Rearrangement and its mechanism
The Pinacol Rearrangement and its mechanism

First alcohol get protonate and becomes a good leaving group. OH2+ leaves to form a carbocation, which is followed by an alkyl shift. The electrons from OH go down to the carbocation to form a double bond and finally, OH gets deprotonated in the last step to make a ketone.


Oxidation of Alcohols


Secondary Alcohols

Secondary alcohols (OH is on a carbon that is attached to two other carbons) can be oxidized to ketones (OH turns into a =O), using a variety of reagents including: Na2Cr2O7 with H2SO4, PCC with CH2Cl2, CrO3 with H3O+ (Jones reagent), acetone and NaOCl/TEMPO, DMP, or 1. (COCl)2, DMSO 2. Et3N.



oxidation of secondary alcohols
oxidation of secondary alcohols

Primary Alcohols

Primary alcohols are molecules where the OH group is on a carbon that is attached to one carbon only. Depending on the reagent primary alcohols can be oxidized into either aldehydes or carboxylic acids. Na2Cr2O7 with H2SO4 and Jones reagent (CrO3 with H3O+) oxidize primary alcohols all the way to carboxylic acids, while PCC with CH2Cl2 stops at the aldehyde.


Oxidation Of Primary And Secondary Alcohols
Oxidation Of Primary And Secondary Alcohols


Tertiary Alcohols

Tertiary alcohols will not be oxidized.


Periodic Acid Oxidation of Glycols

Reagent: HIO4 (periodic acid)

Product: Break the bond between the two carbons with OH groups and turn OH's into =Os.

Periodic Acid Oxidation of Glycols
Periodic Acid Oxidation of Glycols

Alcohol Reaction Cheat Sheet for Organic Chemistry by Brown, Iverson, Anslyn, Foote


Ready For Chemistry Tutoring?

I tutor all levels of chemistry including general and organic chemistry.

Click To Learn More

bottom of page