An efficient chemoenzymatic route to the antidepressants (R)-fluoxetine and (R)-tomoxetine.

(S)-1-Phenyl-3-buten-1-ol (1), prepared in high optical purity by enzymatic resolution of the racemate, is a convenient building block for the synthesis of (R)-fluoxetine (7a) and (R)-tomoxetine (7b). Compound 1 was converted to the title drugs by etherification with appropriate phenols under Mitsunobu conditions, ozonolysis of the terminal double bond, mesylation of the resulting alcohol and substitution with methylamine.