This is a carbon-carbon bond formation reaction that creates a new chiral centre
that allows to increase the complexity of molecules with potential applications in biomedicine.
By convention the enantiomers with opposite stereochemistry around the chiral centres
are designated ephedrine, while pseudoephedrine has same stereochemistry around the chiral carbons.
This is followed by consideration of the phenomena that we know can leave chemists struggling; chiral centres
, restricted rotation, anisotropy, accidental equivalence, non-first-order spectra etc.