The racemic cis-beta-lactam mesylate (I) was treated with NaN3 in DMF to give azide (II). Catalytic hydrogenation of (II) over Pd/C produced reduction to amine with concomitant cyclization to furnish the bicyclic compound (III). Further condensation of (III) with trifluoromethanesulfonyl chloride and pyridine provided a 3:1 mixture of triflates (IV) and (V). After chromatographic isolation of the required triflate (IV), deprotection of its benzyl ester by hydrogenolysis in the presence of PdCl2 yielded the title compound.