反应详情

To a solution of 45D (1.4 g, 4.12 mmol), (R)-2-methylbut-3-enoic acid (0.58 g, 5.79 mmol) in EtOAc (41.2 ml) was added pyridine (1.001 ml, 12.37 mmol). The reaction was cooled down to 0° C. under Ar and propane phosphonic acid anhydride (4.91 ml, 8.25 mmol) was added dropwise. The reaction was then gradually warmed up to rt over night. The reaction mixture was diluted and washed with sat. aq. NaHCO3, aqueous layer back-extracted with EtOAc, combined EtOAc phase washed with brine, dried over MgSO4, filtered, concentrated. The residue was purified by silica gel chromatography to give the desired product (1.47 g, 85%) as an off white foam. 1H NMR (500 MHz, CHLOROFORM-d) δ 8.65-8.60 (m, 1H), 8.19 (d, J=8.3 Hz, 1H), 7.47-7.36 (m, 2H), 7.24-7.18 (m, 3H), 7.16 (dd, J=5.0, 1.4 Hz, 1H), 5.82-5.62 (m, 3H), 5.10-5.01 (m, 4H), 4.86 (d, J=7.2 Hz, 1H), 3.03 (quin, J=7.2 Hz, 1H), 2.62 (tq, J=14.1, 6.9 Hz, 2H), 1.49-1.36 (m, 9H), 1.25 (d, J=7.2 Hz, 3H). MS (ESI) m/z: 422.1 (M+H)+.

1. additionwas added dropwise
2. additionThe reaction mixture was diluted
3. washwashed with sat. aq. NaHCO3, aqueous layer
4. extractionback-extracted with EtOAc, combined EtOAc phase
5. washwashed with brine
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified by silica gel chromatography