To a stirred solution of either ethyl 3-(N-benzyloxycarbonylpyrrolidin-2-yl)-2-propenoate or ethyl-3-(N-benzyloxycarbonylpiperid-2-yl)-2-propenoate (R, or S, or racemate, 10.00 mmol) in anhydrous tetrahydrofuran (75 mL) at -78° C. under nitrogen was added dropwise a solution of diisobutylaluminium hydride (1.0M in hexanes, 12.0 mL, 22.0 mmol, 2.2 eq). The resulting solution was stirred at -78° C. under nitrogen for 30 minutes. The reaction solution was then allowed to warmed to room temperature over the course of 2 hours. A saturated solution of sodium hydrogen carbonate (50 mL) was added, and the aqueous mixture was extracted with ethyl acetate (3×50 mL). The extracts were combined, dried (MgSO4), and evaporated under reduced pressure. Column chromatography of the residue with diethyl ether/hexanes [1:1] afforded either 1-(N-benzyloxycarbonylpyrrolidin-2-yl)-3-hydroxypropene or 1-(N-benzyloxycarbonyl-piperid-2-yl)-3-hydroxypropene.
