反应详情

Polymer bound PPh3 was suspended in THF for 15 min. Methyl 7-hydroxy-8-methyl-2-(trifluoromethyl)-2H-chromene-3-carboxylate from Step 1 (1.5 g, 5.21 mmole) and 2-ethyl butanol (0.96 mL, 7.81 mmole) were added to the above slurry and stirred for 15 min. Ethyl azodicarboxylate (1.23 mL, 7.81 mmole) was added to above mixture dropwise and the mixture was stirred at room temperature overnight. LCMS indicated product formation and that there was no starting material present. The polymer was filtered off through celite pad and the pad was washed with ether. The filtrate was concentrated and the product mixture was suspended in hexane. The undissolved solid was removed by filtration and the filtrate was evaporated and dried in vacuo to afford yellow solid, (1.76 g, 98%): LCMS m/z395.15 (M+Na). 1H NMR (CDCl3/400 MHz) 7.68 (s, 1H), 7.00 (d, 1H, J=8.4 Hz), 6.48 (d, 1H, J=8.4 Hz), 5.68 (q, 1H, J=7.2 Hz), 3.89 (m, 2H), 3.82 (s, 3H), 2.09 (s, 3H), 1.72 (m, 1H), 1.53 (m, 4H), 0.95 (m, 6H). This ester was of suitable purity to use without further purification.

1. stirringthe mixture was stirred at room temperature overnight
2. filtrationThe polymer was filtered off through celite pad
3. washthe pad was washed with ether
4. concentrationThe filtrate was concentrated
5. customThe undissolved solid was removed by filtration
6. customthe filtrate was evaporated
7. customdried in vacuo
8. customto afford yellow solid, (1.76 g, 98%)
9. customto use without further purification