Tributylvinyltin → 3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-7-vinyl-4H-chromeno[4,3-c]isoxazole

Participants

Reaction Steps

To a heterogeneous solution of 7-bromo-3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-4H-chromeno[4,3-c]isoxazole (Preparation 62F, 0.105 g, 0.227 mmol) in dioxane (2.0 mL) in a sealed tube was added sequentially tributyl(vinyl)stannane (0.073 mL, 0.249 mmol) and lithium chloride (0.029 g, 0.680 mmol). The mixture was degassed under reduced pressure and charged with nitrogen (3×). To the mixture was added tetrakis(triphenylphosphine)palladium(0) (0.026 g, 0.023 mmol), and the mixture was stirred under a strong stream of nitrogen for 5 min. The reaction mixture was sealed, immersed in an oil bath at 100° C., and stirred overnight. As it reached 100° C., the solution became near homogeneous. The reaction mixture was concentrated under reduced pressure, and the residue was diluted with dichloromethane (10 mL), filtered through a pad of Celite, and rinsed with dichloromethane (10 mL). The filtrate was concentrated, and the residue was purified by flash silica gel chromatography using a 5% mixture of ethyl acetate in hexane to give 3-(5-phenyl-4-(trifluoromethyl)isoxazol-3-yl)-7-vinyl-4H-chromeno[4,3-c]isoxazole (0.062 g, 0.151 mmol, 67% yield) as a white solid. The product had an HPLC ret. time=3.84 min.−Column: Chromolith SpeedROD 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. LC/MS M+1=411.0.

Provenance & Evidence