Triphenylphosphine → 2-{2-bromo-4-fluoro-6-[(1E)-prop-1-enyl]phenoxy}but-3-enyl 4-methylbenzenesulfonate

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Reaction Steps

To a solution of 2-bromo-4-fluoro-6-[(1E)-prop-1-enyl]phenol (6.37 g, 0.0276 mol), toluene-4-sulfonic acid 2-hydroxy-but-3-enyl ester (8.8 g, 0.0363 mol) and triphenylphosphine (10.12 g, 0.0386 mol) in anhydrous toluene (200 mL) at 0° C. under nitrogen was added a solution of diethyl azodicarboxylate (6.72 g, 0.0386 mol) in anhydrous toluene (100 mL) over 10 minutes then the reaction mixture stirred at room temperature for 19 hours. The reaction was quenched by the addition of water (400 mL), stirred vigorously for 5 minutes and the resulting oily suspension extracted with diethyl ether (300 mL). The organic phase was separated, washed with water (2×500 mL), and saturated brine (400 mL), dried over magnesium sulfate, filtered and concentrated under reduced pressure to afford a yellow oil. Purification by flash chromatography using a solvent gradient of 2 to 10% ethyl acetate in hexane gave 12.11 g (96%) of 2-{2-bromo-4-fluoro-6-[(1E)-prop-1-enyl]phenoxy}but-3-enyl 4-methylbenzenesulfonate as a colorless oil. HRMS: calcd for C20H20BrFO4S+NH4+, 472.05879. found (ESI, [M+NH4]+), 472.0581.

Provenance & Evidence