can anybody please explain optical activity of amines ( do amines actually have a chiral centre ? what is flipping/nitrogen inversion ? and why does this flipping occurs ?)

N-Inversion:- Its the Lone pair (LP) on Nitrogen that is not de-localized (resonance) may undergo inversion from one side of plane (Plane having 3 different substituents attached to N and LP at apex of pyramid) to other side of plane. Further if N atom is part of a ring then factors like ring strain which may arise due to N-LP-Inversion are required to be considered (if inversion may lead to ring strain). The two different arrangement we are getting due to N-inversions can be considered as conformational type of changes. Hence we may conclude if there is N-inversion its CANNOT act as stereo center. Hence the N atom which can not undergo N-inversion (due to non-availability of LP or due to ring strain) and three different substituents are attached to N is stereogenic.

Approved

thank u