反应详情

Compound 21 (2.0 g, 3.41 mmol) in MeOH (10 mL) was treated with a catalytic amount of 1M NaOMe for 5 h, then neutralized with IR-120 (H+), filtered and concentrated. To a solution of the crude product (610 mg, 1.324 mmol), pyridine (700 μL) and DMAP (50 mg) in CH2Cl2 (20 mL), was added BzCl (338 μL, 2.916 mmol). The mixture was refluxed for 5 h under Ar, then concentrated and coevaporated twice with toluene, diluted with CH2Cl2 (100 mL), washed with 10% aq. H2SO4, brine, and sat. aq NaHCO3, dried over Na2SO4, filtered and concentrated. Column chromatography (Hexane/AcOEt, 2:1 to 1:2) of the residue gave 27 (495 mg, 56%) as white white solid; [α]D22 +28.4° (c, 0.5, CHCl3); 1H-NMR (500 MHz, CDCl3), δ 5.50 (d, 1H, J=9.5 Hz, H-2), 5.41 (t, 1H, J=9.5 Hz, H-3), 4.844 (d, 1H, J=10.0 Hz, H-1), 4.74-4.64 (m, 3H), 4.55 (d, 1H, J=12.0 Hz, OCH2CCl3), 3.90 (q, 1H, J=10.0 Hz, H-2), 3.79 (m, 2H, H-5, H-4), 3.42 (d, 1H, J=5.0 Hz, OH), 2.27 (s, 3H, Me); HRMS (M+Cs) calcd for C30H28O8Cl3NSCs 799.9655, found 799.9680.

1. filtrationfiltered
2. concentrationconcentrated
3. temperatureThe mixture was refluxed for 5 h under Ar
4. concentrationconcentrated
5. additiondiluted with CH2Cl2 (100 mL)
6. washwashed with 10% aq. H2SO4, brine, and sat. aq NaHCO3
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated