Epinephrine stereochemistry

The enzymatic introduction of a functional group into a biologically important molecule is not only specific with regard to the location at which the reaction occurs in the molecule (see Chapter 4, Problem 50), but also usually specific in the stereochemistry obtained. The biosynthesis of epinephrine first requires that a hydroxy group be introduced specifically to produce (—(-norepinephrine from the achiral substrate dopamine. (The completion of the synthesis of epinephrine wdl be presented in Problem 71 of Chapter 9.) Only the (—) enantiomer is functional in the appropriate physiological manner, so the synthesis must be highly stereoselective. 

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