4-Hydroxypiperidine (I) was protected as the N-Boc derivative (II), which was then condensed with 1,2-difluoro-4-nitrobenzene (III) in the presence of potassium tert-butoxide, yielding ether (IV). Reduction of the nitro group of (IV) by transfer hydrogenation, followed by treatment of the resulting aniline (V) with benzyl chloroformate, afforded carbamate (VI). After deprotonation of the carbamate group of (VI) with n-butyllithium, reaction with (R)-glycidyl butyrate (VII) generated the chiral oxazolidinone (VIII). Conversion of (VIII) to mesylate (IX) and subsequent displacement with NaN3 provided azide (X). This was reduced to the corresponding amine, which was acetylated with Ac2O to furnish amide (XI). Cleavage of the Boc protecting group of (XI) with trifluoroacetic acid gave piperidine (XII). This was finally acylated with benzyloxyacetyl chloride (XIII) to provide the title amide.
4-Hydroxypiperidine (I) was protected as the N-Boc derivative (II), which was then condensed with 1,2-difluoro-4-nitrobenzene (III) in the presence of potassium tert-butoxide, yielding ether (IV). Reduction of the nitro group of (IV) by transfer hydrogenation, followed by treatment of the resulting aniline (V) with benzyl chloroformate, afforded carbamate (VI). After deprotonation of the carbamate group of (VI) with n-butyllithium, reaction with (R)-glycidyl butyrate (VII) generated the chiral oxazolidinone (VIII). Conversion of (VIII) to mesylate (IX) and subsequent displacement with NaN3 provided azide (X). This was reduced to the corresponding amine, which was acetylated with Ac2O to furnish amide (XI). Cleavage of the Boc protecting group of (XI) with trifluoroacetic acid, followed by acylation of the resulting piperidine with benzyloxyacetyl chloride, provided amide (XII). Finally, hydrogenolysis of the O-benzyl group of (XII) by transfer hydrogenation in the presence of ammonium formate and Pd/C yielded the title hydroxyacetamide.