To a solution of chlorosulfonylisocyanate (28 μL, 0.32 mmol) in dichloromethane (3 mL) was added benzyl alcohol (28 μL, 0.27 mmol). The reaction was stirred at 25° C. for 30 min. A solution of (1R,2S,7R,8S)-5-(7-aminomethyl-1,1-dioxo-1,4-dihydro-1λ6-thieno[2,3-e][1,2,4]thiadiazin-3-yl)-3-(4-fluoro-benzyl)-6-hydroxy-3-aza-tricyclo[6.2.1.02,7]undec-5-en-4-one (prepared as described in Example 33f; 0.10 g, 0.21 mmol) and triethylamine (125 μL, 0.90 mmol) in dichloromethane (3 mL) was then added to the above solution via cannula. The reaction was stirred at 25° C. for 1.5 h. The mixture was diluted with dichloromethane (10 mL) and washed with 1.0 M aqueous hydrochloric acid solution (10 mL). The organic was dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was purified via flash column chromatography (Teledyne Isco RediSep column; 0-3% methanol in dichloromethane) to afford the desired product, benzyl (N-{3-[(1R,2S,7R,8S)-3-(4-fluoro-benzyl)-6-hydroxy-4-oxo-3-aza-tricyclo[6.2.1.02,7]undec-5-en-5-yl]-1,1-dioxo-1,4-dihydro-1λ6-thieno[2,3-e][1,2,4]thiadiazin-7-ylmethyl}amino)sulfonylcarbamate (0.13 g, 0.18 mmol, 86%), as a white solid. 1H NMR (400 MHz, CDCl3) δ: 1.19-1.77 (6H, m), 2.57-2.58 (1H, m), 2.83-2.88 (2H, m), 3.46 (1H, m), 4.22 (1H, d, J=15.6 Hz), 4.50 (2H, bs), 5.12-5.18 (3H, m), 6.06 (1H, bs), 7.02-7.07 (3H, m), 7.19-7.23 (2H, m), 7.33-7.39 (5H, m).
