反应详情

温度

-72 °C

A solution of 1D (1.75 g, 5 mmol) in dry THF (50 mL) under argon was cooled to −72° C. and treated dropwise with n-butyllithium (2.5 M in hexanes, 4 mL, 10 mmol) at such a rate so that the temperature did not exceed −65° C. Upon completion of the addition, the reaction was stirred at −72° C. for an additional hour. N-formyl piperidine (1.1 mL, 10 mmol) was added, and then the reaction was allowed to warm up to 0° C. and maintained there for an hour. The solution was quenched by the addition of 1 M aqueous HCl to bring the pH to 6-8. The reaction was stirred at RT for 5 min, extracted with EtOAc (3×50 mL). The combined organic layers were washed with saturated NaCl, dried over Na2SO4, filtered, and evaporated under reduced pressure. The residue was purified by silica gel (110 g) column chromatography, eluting with a gradient of EtOAc (0-30%) in hexane to give the title compound as a yellow solid (1.02 g, 68%). LC/MS (method A): retention time=4.24 min, (M+H-tBu)+=243. 1H NMR (CDCl3, 400 MHz): δ 10.25 (s, 1H), 10.15 (s, 1H), 8.86 (d, J=9.0 Hz, 1H), 8.00-8.02 (m, 2H), 7.87(d, J=9.0 Hz, 1H), 7.38-7.47 (m, 3H) 1.56 (s, 9H). 13C NMR (100 MHz, CDCl3): δ 197.93, 153.16, 151.18, 138.26, 138.14, 136.51, 129.45, 129.27, 127.50, 126.78, 125.80, 82.03, 28.64.

1. customdid not exceed −65° C
2. additionUpon completion of the addition
3. temperatureto warm up to 0° C.
4. temperaturemaintained there for an hour
5. customThe solution was quenched by the addition of 1 M aqueous HCl
6. stirringThe reaction was stirred at RT for 5 min
7. extractionextracted with EtOAc (3×50 mL)
8. washThe combined organic layers were washed with saturated NaCl
9. dry with materialdried over Na2SO4
10. filtrationfiltered
11. customevaporated under reduced pressure
12. customThe residue was purified by silica gel (110 g) column chromatography
13. washeluting with a gradient of EtOAc (0-30%) in hexane