反应详情

Oxalyl chloride (0.74 g, 5.84 mmol) in DCM (2 mL) was added slowly to a stirred solution of tert-butyl(dimethyl)silyl 2-{[tert-butyl(dimethyl)silyl]oxy}-4-(methylsulfonyl)butanoate (Step 2) (2.00 g, 4.87 mmol) in DCM (8 mL) and DMF (three drops). After 1 h at ambient temperature, gas evolution had subsided and the reaction mixture was concentrated in vacuo to remove excess oxalyl chloride. The residue was dissolved in DCM (8 mL) and pyridine (0.50 g, 6.33 mmol) and 2-amino-5-picoline (0.58 g, 5.36 mmol) were added. The reaction mixture was kept at ambient temperature for 1 h. Water was added and the two phases were separated. The aqueous phase was extracted with DCM. The organic extracts were combined and washed with water, dried over MgSO4 and concentrated in vacuo. The residue was purified with column chromatography (silica gel, eluting with DCM/EtOAc:10/1) to give the title compound as a colourless oil (1.23 g), 1H NMR (300 MHz, CDCl3) δ 8.92 (br s, 1H), 8.13 (d, 1H), 8.08 (d, 1H), 7.53 (dd, 1H), 4.44 (t, 1H), 3.19 (m, 1H), 3.05 (m, 1H), 2.90 (s, 3H), 2.44 (m, 1H), 2.28 (m, 4H), 0.97 (s, 9H), 0.19 (d, 6H).

1. concentrationthe reaction mixture was concentrated in vacuo
2. customto remove excess oxalyl chloride
3. dissolutionThe residue was dissolved in DCM (8 mL)
4. waitThe reaction mixture was kept at ambient temperature for 1 h
5. customthe two phases were separated
6. extractionThe aqueous phase was extracted with DCM
7. washwashed with water
8. dry with materialdried over MgSO4
9. concentrationconcentrated in vacuo
10. customThe residue was purified with column chromatography (silica gel, eluting with DCM/EtOAc:10/1)