m-Chloroperbenzoic acid → [3-(4-Bromophenyl)-4,5-dihydroisoxazol-5-yl]methyl di-tert-butyl phosphate

Participants

Reaction Steps

[3-(4-Bromophenyl)-4,5-dihydroisoxazol-5-yl]methanol (2.5 g, 9.8 mmol) was dissolved in dichloromethane (100 ml). To this solution, di-tert-butyl-N,N-diethylphosphoroamidite (3.3 ml, 11.7 mmol) and 1H-tetrazole (1.2 g, 17.6 mmol) were added sequentially. After 1.5 h stirring at room temperature, the solution was cooled to 0° C. and m-chloroperbenzoic acid (70%; 3.6 g, 14.7 mmol) was added. After 1.5 h the reaction was warmed to room temperature; a sodium bisulfite solution was added and the mixture stirred about 5 min. After diluting with dichloromethane, the aqueous layer was extracted with dichloromethane (2×), and the combined organics were washed with saturated sodium bicarbonate solution, brine, and dried over magnesium sulfate. The crude residue was purified by chromatography on silica gel using 0-5% methanol in dichloromethane as the eluent, resuliting in 4.1 g of the desired product.

Provenance & Evidence