Reaction Steps
n-BuLi (1.94 M in hexane, 10 mL) was added to a solution of 6-bromo-1,3-benzodioxol (16.6 mmol) in THF (65 mL) at -78° C. The reaction mixture was stirred for 40 min at -78° C. and CuCN (744 mg, 8.3 mmol) was added. After stirring at -78° C. for 1 h, a solution of aziridine 3 (1.27g, 3.95 mmol) in THF (10 mL) was added, followed by BF3.Et2O (0.40 mL). The reaction mixture was allowed to warm slowly to room temperature while stirring. After addition of saturated aqueous NH4Cl solution (10 mL), the organic layer was separated and the aqueous phase was extracted with ethyl acetate (4×10 mL). The combined organic layers were dried over Na2 SO4 and concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, CH2Cl2 /acetone, 12:1) to give tosylamide 5 (552 mg, 32%) as a white solid: mp 75°-76° C.; [α]D22 +44.6° (c 1.16, CHCl3); 1H NMR (200 NMz, CHCl3) δ 7.43 (d, J=8.2 Hz, 2H), 7.09 (d, J=8.2 Hz, 2H), 6.49 (m, 3H), 5.95 (m,3H), 5.76 (dd, J=9.9, 1.6 Hz, 1H), 5.34 (d, J=8.5 Hz, 1H), 4.61 (t, J=4.46 Hz, 1H), 4.13 (dd, j=9.1, 6.0 Hz, 1H), 3.51 (q, J=9.2 Hz, 1H), 3.13 (bd, J=9.8 Hz, 1H), 2.38 (s, 3H), 1.50 (s, 3H), 1.35 (s, 3H); 13C NMR (50 MHz, C6D6) δ 147.9 (C), 146,9 (C), 141.6 (C), 140.6 (C), 135.1 (CH), 135.0 (C), 129.0 (CH), 126.9 (CH), 124.3 (CH), 122.3 (CH), 109.9 (C), 109.2 (CH), 108.4 (CH), 100.7 (CH2), 78.2 (CH), 72.7 (CH), 59.6 (CH) 47.5 (CH), 28.3 (CH3), 26.3 (CH3), 21.1 (CH3); HRMS: calculated for C23H25 O6NS 443.1403, found 443.1416.
