Boron tribromide → 4-Cyano-4-(3-hydroxyphenyl)-3,4,5,6-tetrahydro-2H-pyran

Beteiligte Stoffe

Reaktionsschritte

To a dichloromethane (80 ml) solution of 4-cyano-4-(3-methoxyphenyl)-3,4,5,6-tetrahydro-2H-pyran (2.32 g, 10.35 mmol) cooled to 0° C. was added boron tribromide (3.15 ml, 33.3 mmol) dropwise over 10 min. The ice-bath was removed and the reaction mixture stirred at ambient temperature for 19 h, and then at reflux for 4 h. The reaction mixture was cooled and poured into water (150 ml). The organic layer was separated and the aqueous layer was extracted with ethyl acetate (50 ml×3). The combined organic extracts were washed with brine (50 ml), dried (MgSO4) and concentrated in vacuo. The crude product was crystallized from isopropyl ether to afford titled compound as off-white solids (1.43 g, 66%).

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