To a well stirred solution of (−)-(1R,2S,3R,5R)-3-amino-5-(hydroxymethyl)cyclopentane-1,2-diyl dibenzoate hydrochloride (6) (10.0 g, 25.5 mmol) in mixture of acetonitrile/water (1:1) was added sodium nitrite (8.8 g, 127.8 mmol) by portion wise at 0° C. After 15 minutes 50% aqueous acetic acid solution was added drop wise over a period of 0.5 hr and the mixture was vigorously stirred for 2 hr. The organic solvent was removed under reduced pressure and the rest of mixture was quenched with water. The aqueous phase was extracted with EtOAc (50 mL×3). The combined organic layers were dried over Na2SO4, filtered and the solvent was removed under reduced pressure. The residue was purified by flash silica gel column chromatography (20% EtOAc/hexane) to give compound 7. [α]24D −156° (c 1.0, CHCl3); 1H NMR (500 MHz, DMSO-d6): δ 8.05 (m, 2H), 7.89 (m, 2H), 7.52 (m, 2H), 7.38 (m, 2H), 7.28 (m, 2H), 6.11 (m, 3H), 5.54 (m, 1H), 3.87-3.82 (m, 2H), 3.27 (m, 1H), 2.29 (m, 1H). HR-MS Calcd. For (C25H29NO7+H)+ 339.1154, found 339.1286.
