[kriggy]

Hi there,
I know that moshers acid is used to determine absolute stereochemistry of chiral center by forming an ester or amide and then using ¹⁹F-NMR. So I have a compound with unknown stereochemistry make an ester, but how exactly is the streochemistry determined from the spectrum?

[discodermolide]

You do it by the ration of the peak areas.
But you need to know which peak belongs to which diastereoisomer. Usually you need to make one pure enantiomer first and then use a chiral HPLC.
You could use a chiral shift reagent as long as you have easily identifiable peaks in the H-NMR. This may give a strong hint as to the (R) or (S) content of the sample.

[kriggy]

Ok, Im doing an article rewiew for seminar (DOI 10.1002/ejoc.201403582) where there using this method so I wanted to understand the procedure.
So is it like this:
(compounds Im talking about)
have single enantiomer (but dont know which one it is) which is protected then I make two esters, one with R and the other with S Mosher´s acid.Then I run NMR. Is it then that for example the RR or SS configuration gives higher intensities than SR or RS?

[discodermolide]

The RR should have a higher area than the SR and the SS larger than the SR.