A solution of aluminum chloride (14.54 g) in 500 mL of anhydrous diethyl ether is added dropwise to a suspension of lithium aluminum hydride (12.41 g) in 500 mL of tetrahydrofuran. The mixture is stirred at room temperature for 30 minutes. A solution of 1-(1,4-dioxaspiro[4.5]dec-7-yl carbonyl)-1,2,3,6-tetrahydro-4-phenylpyridine (Step B) in 500 mL of tetrahydrofuran is added dropwise. The mixture is stirred at room temperature overnight, and it is quenched by careful addition of 13 mL of water, followed by 59 mL of 25% aqueous sodium hydroxide solution. The resulting mixture is stirred at room temperature for 2 hours, filtered through celite, and concentrated in vacuo. The title compound is obtained (90.40 g) as a light yellow oil (silica; Rf =0.2; 1% methanol, 99% chloroform).
