Reaction Steps
12-Aza-tricyclo[7.2.1.0*2,7*]dodeca-2(7),3,5-trien-4-ylamine (572 mg, 3.3 mmol), di-tert-butyl dicarbonate (1.6 g, 7.2 mmol), triethylamine (1.0 mL, 7.2 mmol) were stirred at room temperature in tetrahydrofuran (20 mL) for 18 h. The reaction was then concentrated and purified with silica gel chromatography (0-30% EtOAc in hexanes) to obtain 4-tert-Butoxycarbonylamino-12-aza-tricyclo[7.2.1.0*2,7*]dodeca-2(7),3,5-triene-12-carboxylic acid tert-butyl ester as a white solid (1.1 g, 90%). MS (m/e) 375 (M+1). 92b) Tert-butyllithium (1.7M, 2.3 mL, 4.0 mmol) was added dropwise to a solution of 4-tert-butoxycarbonylamino-12-aza-tricyclo[7.2.1.0*2,7*]dodeca-2(7),3,5-triene-12-carboxylic acid tert-butyl ester (450 mg, 1.2 mmol) in THF (5 mL) at −78° C. The solution was then allowed to warm slowly to −20° C. and stir at that temperature for 1 h before cooling again to −78° C. and adding trimethyl borate (0.37 mL, 3.2 mmol) via syringe. The reaction was allowed to warm to room temperature slowly and stir overnight. The reaction was quenched with methanol (1 mL) and hydrogen peroxide (30% solution, 0.37 mL, 3.6 mmol) was added to the reaction and allowed to stir at room temperature for 2 h. The mixture was then adjusted to neutral pH with 1 N HCl, extracted with CH2Cl2 (3×10 mL), dried over MgSO4, filtered and concentrated. The resulting residue was purified with silica gel chromatography (0-50% EtOAc in hexanes) to obtain 4-tert-Butoxycarbonylamino-3-hydroxy-12-aza-tricyclo[7.2.1.0*2,7*]dodeca-2(7),3,5-triene-12-carboxylic acid tert-butyl ester as a brown foam (260 mg, 55%). 1HNMR (400 MHz, CDCl3) δ 7.7 (m, 1H), 7.5 (s, 1H), 7.1 (d, 1H, J=8.1 Hz), 6.9 (m, 1H), 4.5 (d, 1H, J=7.8 Hz), 4.1 (m, 1H), 3.1 (dd, 1H, J=14.4, 4.9 Hz), 2.9 (dd, 1H, J=14.4, 4.9 Hz), 2.7 (dd, 1H, J=18.2, 8.1 Hz), 2.6 (dd, 1H, J=18.2, 10.6 Hz), 2.2-2.1 (m, 1H), 1.5-1.3 (m, 19H); 1H-1H COSY interactions between peak at 7.7 and 7.1 ppm; MS (m/e) 391 (M+1).
