(E)-4-(2,4-dichlorophenyl)but-3-en-2-one

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A round bottom flask equipped with magnetic stirrer and nitrogen inlet was charged with 2,4-dichlorobenzaldehyde (1.75 g, 10.0 mmol), acetone (44.1 ml, 0.60 mol) and water (20 ml). The mixture was cooled to 0° C. and a solution of sodium hydroxide (0.44 g, 11.0 mmol) in water (20 ml) was added drop wise during 1 hour to the vigorous stirred suspension. The reaction mixture was stirred for an additional 1.0 hour. The reaction mixture was concentrated in vacuo, poured onto 10% HCl (100 ml) and extracted with ethyl acetate (3×50 ml). Combined organic layers were dried over anhydrous sodium sulfate. The solvent was removed in vacuo and the residue was purified by flash chromatography over silica gel (350 g) (eluent: n-hexane/ethyl acetate 1:1) to afford 1.9 g (88% of theory) of (E)-4-(2,4-dichloro-phenyl)-but-3-en-2-one in form of a pale yellow oil. A round bottom flask equipped with magnetic stirrer and nitrogen inlet The reaction mixture was concentrated in vacuo poured onto 10% HCl (100 ml) extracted with ethyl acetate (3×50 ml) Combined organic layers were dried over anhydrous sodium sulfate The solvent was removed in vacuo the residue was purified by flash chromatography over silica gel (350 g) (eluent: n-hexane/ethyl acetate 1:1)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A round bottom flask equipped with magnetic stirrer, nitrogen inlet and additional funnel was charged with trimethylsulfoxonium iodide (0.61 g, 2.78 mmol), DMSO (10 ml) and powdered sodium hydroxide (97 mg, 2.44 mmol). The suspension was stirred for 1.0 hour at ambient temperature to yield a solution. So prepared solution was added drop wise at ambient temperature to a solution of (E)-4-(2,4-dichloro-phenyl)-but-3-en-2-one (0.50 g, 2.32 mmol) prepared as described in example P30 in DMSO (10 ml). The reaction mixture was stirred for 0.5 hours, poured onto ice water (100 ml) and extracted with ether (3×25 ml). Combined organic layers were washed with water, brine and dried over anhydrous sodium sulfate. The solvent was removed in vacuo and the residue was purified by flash chromatography over silica gel (25 g) (eluent: n-hexane/ethyl acetate 10:1) to afford 0.33 g (62% of theory) of trans 1-[2-(2,4-dichloro-phenyl)-cyclopropyl]-ethyanone in form of an oil. A round bottom flask equipped with magnetic stirrer, nitrogen inlet and additional funnel to yield a solution So prepared solution prepared The reaction mixture was stirred for 0.5 hours poured onto ice water (100 ml) extracted with ether (3×25 ml) Combined organic layers were washed with water, brine dried over anhydrous sodium sulfate The solvent was removed in vacuo the residue was purified by flash chromatography over silica gel (25 g) (eluent: n-hexane/ethyl acetate 10:1) to afford 0.33 g (62% of theory) of trans 1-[2-(2,4-dichloro-phenyl)-cyclopropyl]-ethyanone in form of an oil