反応手順
To a 0.11 M solution of (+)-TBZ (15) in ethanol at 0° C. was added NaBH4 (2.85 eq). The reaction mixture was allowed to stir for 60 min. at room temperature. The solvent was carefully removed under reduced pressure, and the residue was taken up in dichloromethane and washed with three portions of saturated aqueous K2CO3. The aqueous washings were back extracted with two portions of dichloromethane. The combined organic extracts were dried (MgSO4), filtered, and concentrated under reduced pressure to provide a colorless oil that crystallized on standing under high vacuum. Purification of the crude product was achieved by chromatography on SiO2 (2.5-5% MeOH—CH2Cl2, elution was observed at 285 nm) UV active fractions were reanalyzed by TLC. Two products, 18 and 19, were isolated from this procedure. The major product 18 was a colorless solid 74%: [α]26D +48 (c 0.30, CH2Cl2) 1H NMR (CD2Cl2) δ 0.93 (d, J=6.6 Hz, 3H), 0.95 (d, J=6.6 Hz, 3H), 1.04 (ddd, J=14.6, 8.7, 4.3 Hz, 1H), 1.42 (dd, J=20.2, 11.4 Hz, 1H), 1.59 (ddd, J=13.7, 9.6, 3.3 Hz, 1H), 1.64-1.78 (m, 2H), 1.96 (apparent t, J=11.4 Hz, 1H), 2.27 (br s, 1H), 2.40-2.48 (m, 1H), 2.54 (ddd, J=12.3, 3.7, 2.3 Hz, 1H), 2.60-2.67 (m, 1H), 2.95-3.09 (m, 3H), 3.11 (apparent d, J=11.1 Hz, 1H), 3.35 (ddd, J=10.4, 10.4, 4.5 Hz, 1H), 3.80-3.81 (m, 6H), 6.60 (s, 1H), 6.69 (s, 1H); 13C NMR (CD2Cl2) δ 21.61, 24.02, 25.33, 29.30, 39.68, 40.81, 41.58, 51.83, 55.74, 55.91, 60.02, 60.92, 74.32, 108.42, 111.73, 126.68, 129.76, 147.35, 147.61; HRMS-(ESI+) calcd for (C19H29NO3+H) ([M+H]+ 320.2226, found 320.2242. The minor product 19 was a yellow oil 4%: 1H NMR (CD2Cl2) δ 0.94 (d, J=6.6 Hz, 3H), 0.96 (d, J=6.6 Hz, 3H), 1.13-1.20 (m, 1H), 1.24-1.34 (m, 2H), 1.60-1.77 (m, 2H), 1.89-2.00 (m, 1H) 2.36-2.44 (m, 2H), 2.53 (ddd, J=10.5, 10.5, 3.8 Hz, 1H), 2.58-2.70 (m, 2H), 2.91-2.98 (m, 1H), 2.98-3.09 (m, 1H), 3.48 (apparent d, J=11.6 Hz, 1H), 3.80-3.82 (apparent s, 6H), 4.07 (apparent d, J=3.1 Hz, 1H), 6.60 (s, 1H), 6.68 (s, 1H); 13C NMR (CD2Cl2) δ 22.74, 22.81, 24.87, 29.30, 37.83, 38.87, 39.42, 52.44, 55.76, 55.96, 56.32, 56.43, 67.88, 108.45, 111.78, 127.18, 130.38, 147.30, 147.54.
