|Chapter 17: Aldehydes and Ketones. Nucleophilic Addition to C=O|
Reactions of Primary Amines
NUCLEOPHILIC ADDITION OF A PRIMARY AMINE GIVING AN IMINE
An acid/base reaction. Protonation of the carbonyl activates it and makes it more susceptible to attack by a neutral nucleophilic like the N of a primary amine.
Attack of the N nucleophile at the electrophilic C of the C=O group with the electrons from the π bond going to the +ve O.
An acid/base reaction. Removal of the proton neutralises the +ve charge on the N and forms the carbinolamine intermediate.
To form the imine we need to dehydrate. However, before -OH leaves it needs to be protonated, so a simple acid/base reaction.
Use the electrons of the N to help push out the leaving group, a neutral water molecule, forming a C=N in the form of an iminium ion.
An acid/base reaction. Deprotonation of the iminium N reveals the imine product and regenerates the acid catalyst.
|© Dr. Ian Hunt, Department of Chemistry, University of Calgary|