Isopropanol → 1-(2-Chloro-1-cyclopentenyl)ethanol

Under an argon atmosphere, 2-chloro-1-cyclopentenecarbaldehyde (630 mg, 4.82 mmol) was dissolved in anhydrous tetrahydrofuran (19 ml), methylmagnesium bromide (1.4M toluene solution, 4.1 ml) was added dropwise at 0° C., and the mixture was stirred at room temperature for 30 minutes. Isopropanol (2 ml) was added at 0° C., and the solvent was evaporated under reduced pressure. 1N Hydrochloric acid was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel chromatography (hexane:ethyl acetate=10:1-6:1) to give the title compound (294 mg, 2.01 mmol, 41.6%).