Chapter 10: Alcohols
Table of contents of main topics:
Nomenclature of Alcohols
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.
If the OH group is on a ring, start counting from the carbon that has the OH group.
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.
If there are multiple OH groups, use "diol" (2), and "triol"(3)...
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.
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.
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.