49 mg of (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-yl (1S,2R)-3-[(2,3-dihydro-1,4-benzodioxin-6-ylsulfonyl)(isobutyl)amino]-2-hydroxy-1-(4-hydroxy benzyl)propylcarbamate, 20 mg of m-cyanobenzylchloride, 20 mg of cesium carbonate and 0.5 ml of dimethyl formamide were stirred at rt for 5 h. The mixture was diluted with ethyl acetate and extracted with water. Chromatography on silica gel (1:1 ethylacetate/hexane) gave the title compound as a white solid (20 mg). 1H NMR: 0.87 (6H, dd), 1.58 (2H, m), 1.8 (1H, m), 2.75 (2H, m), 2.9 (4H, m), 3.1 (1H, m), 3.62 (3H, m), 3.8 (3H, m), 3.95 (1H, m), 4.25 (4H, m), 4.95 (2H, m), 5.0 (2H, s), 5.62 (1H, d), 6.82 (2H, d), 6.92 (1H, d), 7.1 (2H, d), 7.2 (2H, m), 7.45 (1H, t), 7.6 (2H, m), 7.75 (1H, s). MS:722(M+H)
