反应详情

温度

60 °C

A solution of 840 mg (1.2 mmol, 0.05 eq) of PdCl2(PPh3)2 in 60 mL of dry toluene was stirred in a 200 mL 3-necked flask equipped with a mechanical stirrer at room temperature under argon. To this mixture was sequentially added 5.90 grams (23.96 mmol, 1.0 eq) of boronic acid 10 and 3.81 grams (26.36 mmol, 1.1 eq) of 4-Methyl-oxazole-5-carbonyl chloride 8. Lastly, 11.0 grams (47.92 mmol, 2.0 eq) of finely powdered K3PO4.H2O was added to the flask. The heterogenous mixture was stirred vigorously with the mechanical stirrer and warmed to 60° C. The solution was stirred at this temperature until complete by TLC (1:1 hexane:EtOAc). The reaction rate was highly dependent on the rate of stirring. Upon completion (˜2 hours) the reaction was cooled to room temperature and the dark mixture was passed through a pad of CELITE. The CELITE was washed with EtOAc and the combined organic fractions were then washed with water and the aqueous layer was back extracted with EtOAc. The combined EtOAc extracts were washed with brine and dried over MgSO4. After concentration, silica gel chromatography (hexane/EtOAc) gave 5.85 grams (78%) of 11a as a brown oil, Rf 0.56 (1:1 hexane:EtOAc). 1H-NMR (500 MHz, CDCl3): 7.91 (1H, s), 7.75 (1H, d, J=7.8 Hz), 7.53 (1H, m), 7.37 (2H, m), 4.14 (1H, q, J=7.1 Hz), 2.36 (3H, s), 1.50 (3H, d, J=7.1 Hz), 0.11 (9H, s). 13C-NMR (500 MHz, CDCl3): 185.52, 152.11, 146.91, 145.45, 142.46, 136.31, 131.69, 128.54, 128.24, 126.55, 109.40, 86.21, 29.60, 24.72, 14.18, 0.22. IR (cm−1): 2957 (m), 2164 (m), 1655 (s), 1579 (s), 1354 (m), 1248 (s), 904 (s), 843 (s), 760 (s). HRMS (EI) calcd. for C18H21NO2Si: 311.1342. found 311.1356.

1. customequipped with a mechanical stirrer at room temperature under argon
2. stirringof stirring
3. temperatureUpon completion (˜2 hours) the reaction was cooled to room temperature
4. washThe CELITE was washed with EtOAc
5. washthe combined organic fractions were then washed with water
6. extractionthe aqueous layer was back extracted with EtOAc
7. washThe combined EtOAc extracts were washed with brine
8. dry with materialdried over MgSO4
9. concentrationAfter concentration, silica gel chromatography (hexane/EtOAc)