DOUBLE_DEXTER_FINN_AGAIN
(1S,2S)-1-phenyl-1-carbomethoxy-2-methylaminopropane
from
(1R,2S)-1-phenyl-1-hydroxy-2-methylaminopropane
Actually, I think the hydroxyl group may switch around the stereochemistry of the one spot after it undergoes a substitution reaction. I was never very good with the whole Khan Ingold Prelog (R,S) nomenclature.
Anyway, if that is the case, then this is the correct precursor:
(1S,2S)-1-phenyl-1-hydroxy-2-methylaminopropane
BUT it undergoes 2 substitution reactions, so the former would be correct.
Errg, Forget Stereochemistry! All I Know Is That Ephedrine Comes In 4 Stereochemicals, And One Of Them Is Correct. Specifically, It Has A (2S).