Methyl vinyl ketone → 4,4-Bis(3-fluorophenyl)cyclohexenone

Participants

Reaction Conditions

Reaction Steps

Butenone (50.4 cc) is added to a solution of bis-(3-fluorophenyl)acetaldehyde (144.5 g) in ethyl ether (500 cc) and then, after cooling to 0° C., a solution of potassium hydroxide (13.9 g) in ethanol (89 cc) is added dropwise. The reaction mixture is stirred for 2 h at 0° C. and then for 16 hours at 25° C. and diluted with ethyl acetate (300 cc) and water (500 cc). The aqueous phase is washed with ethyl acetate (300 cc). The combined organic phases are washed with saturated sodium chloride solution (500 cc), dried over magnesium sulphate and concentrated under reduced pressure (2.7 kPa). The residue is chromatographed (in two passes) on silica gel (particle size 0.04-0.063 mm, columns 8.5 cm in diameter and 34 cm high), eluting under a nitrogen pressure of 0.5 bar with a mixture of cyclohexane and ethyl acetate (90/10). 4,4-bis-(3-Fluorophenyl)-cyclohexenone (90.3 g) is obtained in the form of white crystals. m.p.=95° C.

Provenance & Evidence