Radical bromination of 3-(1,1,2,2-tetrafluoroethoxy)toluene (I) by means of N-bromosuccinimide in the presence of AIBN provided benzyl bromide (II), which was then condensed with 3-phenoxyaniline (III) in refluxing cyclohexane to afford (IV). Alternatively, (IV) was obtained by reductive condensation of 3-(1,1,2,2-tetrafluoroethoxy)benzaldehyde (A) with 3-phenoxyaniline (III) in the presence of sodium triacetoxyborohydride. The condensation of the secondary amine (IV) with commercially available trifluoromethyloxirane (V) of unspecified enantiomeric composition in the presence of ytterbium triflate furnished a 1:7 mixture of enantiomeric amino alcohols (VI). The title compound was then isolated from (VI) as the minor enantiomer by means of preparative chiral HPLC.
The chiral (R)-(+)-epoxide (X) was synthesized by asymmetric reduction of 3-bromotrifluoroacetone (VII) using (+)-B-chlorodiisopinocampheylborane (VIII), followed by intramolecular cyclization of the resulting (R)-bromohydrin (VIII) in aqueous NaOH. Finally, reaction of amine (IV) with the chiral epoxide (X) furnished the desired enantiomer.