Diisobutylaluminum hydride → 2-(1-(4-Chloro-3-methoxyphenyl)piperidin-4-ylidene)ethanol

A solution of methyl 2-(1-(4-chloro-3-methoxyphenyl)piperidin-4-ylidene)acetate (275 mg, 0.930 mmol) in anhydrous THF (3 mL) was cooled to −78° C. and then treated with DIBAL-H (3.72 mL of a 1.0 M solution in toluene, 3.72 mmol). The reaction was stirred at −78° C. for 2.5 h and then quenched with EtOAc. After it warmed to 0° C., the mixture was treated with saturated potassium sodium tartrate solution and stirred vigorously for 20 min. The resulting mixture was extracted with EtOAc. The extract was dried (Na2SO4) and concentrated to give a yellow oil, which was purified by flash chromatography (4 g silica gel cartridge and gradient elution with EtOAc/hexanes) to give 2-(1-(4-chloro-3-methoxyphenyl)piperidin-4-ylidene)ethanol (253 mg, 0.945 mmol, 102% yield) as a yellow oil. 1H-NMR (400 MHz, CDCl3) δ ppm 7.18 (1 H, d, J=8.79 Hz), 6.48 (1 H, d, J=16.92 Hz), 6.43 (1 H, s), 5.50 (1 H, t, J=7.03 Hz), 4.18 (2 H, d, J=7.03 Hz), 3.87 (3 H, s), 3.22 (4 H, dt, J=9.50, 5.68 Hz), 2.39-2.48 (2 H, m), 2.32-2.39 (2 H, m).