1,8-Diazabicyclo(5.4.0)undec-7-ene → 2-(4-bromophenyl)-3,6-dihydro-2H-pyran

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Reaction Conditions

Reaction Steps

To a solution of 4-bromo-2-(4-bromophenyl)tetrahydro-2H-pyran (320 mg, 1.00 mmol) in toluene (5 mL) was added 1,8-Diazabicyclo[5.4.0]undec-7-ene (304 mg, 2.00 mmol). The mixture was stirred at 100° C. for 16 hours. The mixture was then diluted with ethyl acetate and water. The organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated. The residue was purified by silica gel chromatography to give the title compound (150 mg) which contained some impurity of 4-bromobenzaldehyde. 1H NMR (400 MHz, CDCl3) δ ppm 7.48 (d, 2H) 7.30 (d, 2H) 5.92 (m, 1H) 5.82 (m, 1H) 4.52 (dd, 1H) 4.36 (m, 2H) 2.27 (m, 2H).

Provenance & Evidence