[Cl:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]=O)=[CH:4][CH:3]=1.F[B-](F)(F)F.[CH:15]1([S+](C2C=CC=CC=2)C2C=CC=CC=2)[CH2:17][CH2:16]1.CC(C)([O-:34])C.[K+].F[B-](F)(F)F.[H+]>C1COCC1.CCOCC>[Cl:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]2[CH2:17][CH2:15][C:16]2=[O:34])=[CH:4][CH:3]=1To a stirred solution of 4-chloro-benzaldehyde (142 mg, 1 mmol) and cyclopropyldiphenylsulfonium tetrafluoroborate (317 mg, 1 mmol) in 10 ml dry THF, cooled to 0° C., was added dropwise, with stirring, a slurry of potassium tert. butoxide (1.4 ml 1M). After addition was complete the reaction was stirred 30 min. and 1M tetrafluoroboric acid (10% in THF) (10 ml) was added. The mixture was allowed to warm to room temperature and was taken up into ether and the ether solution was washed with saturated NaHCO3, brine and water and was dried. Filtration and concentration by rotary evaporation gave an oil. Chromatography over silica gel and elution i-Hx:ether 5:1 gave 2-(4-chlorophenyl)cyclobutanone as an oil. (180 mg, 83%).
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