反应详情

A suspension of the product of Step A (0.3 g; 1.22 mmol) in HMDSA (2 ml) and saccharine (0.1 g) was refluxed under N2 until reaction became homogenous (˜30 min). After cooling to room temperature, the HMDSA was removed in vacuo and the residue was diluted to 4 ml with anhydrous THF. At the same time ZnCl2 (0.2 g; 1.47 mmol) was heated to ˜110° C., in separate flask, in vacuo, cooled to room temperature under N2 and diluted to 4 ml with anhydrous THF. To it 0.5 M prop-1-ynyl-magnesium bromide in THF (4.9 ml; 2.45 mmol) was added at room temperature and this was stirred for 10 min under N2. To it a solution of silinated product of Step A was added, followed by Pd(PPh3)4 (0.11 g; 0.095 mmol) and CuI (0.05 g; 0.26 mmol). After stirring for 1 h at room temperature under N2, MeOH (5 ml) was added and solvents were removed under reduced pressure. The residue was diluted to 20 ml with EtOAc, washed with saturated NH4Cl (2×5 ml), H2O (10 ml), brine, dried anhydrous MgSO4, filtered and filtrate evaporated to dryness under reduced pressure. The residue was purified by FCC (SiO2, CH2Cl2) to give title compound (0.16 g; 78%), as colourless solid. 1H-NMR (CDCl3) 2.14 (s, 3H); 6.26 (s, 1H); 6.97 (d, 1H, J=8.5 Hz); 7.46 (dd, 1H, J=2.1 Hz, 8.5 Hz); 7.57 (d, 1H, 2.1 Hz).

1. temperaturewas refluxed under N2 until reaction
2. custom(˜30 min)
3. customthe HMDSA was removed in vacuo
4. additionthe residue was diluted to 4 ml with anhydrous THF
5. temperaturecooled to room temperature under N2
6. stirringAfter stirring for 1 h at room temperature under N2
7. customsolvents were removed under reduced pressure
8. additionThe residue was diluted to 20 ml with EtOAc
9. washwashed with saturated NH4Cl (2×5 ml), H2O (10 ml), brine, dried anhydrous MgSO4
10. filtrationfiltered
11. customfiltrate evaporated to dryness under reduced pressure
12. customThe residue was purified by FCC (SiO2, CH2Cl2)