A solution of 4-benzo[1,3]dioxol-5-yl-cyclohex-3-enone (as prepared in the previous step, 680 mg, 3.15 mmol) and azetidin-3-yl-carbamic acid tert-butyl ester (BetaPharma, 542 mg, 3.15 mmol) in DCM (10 mL) was treated with NaBH(OAc)3 (Aldrich, 2.0 g, 9.45 mmol) at room temperature. The reaction was stirred for 4 hours and quenched with saturated sodium bicarbonate. The organic layer was separated and the aqueous layer was extracted 3 times with DCM. The combined organic layers were dried over anhydrous Na2SO4, filtered and concentrated to give the crude product, which was then purified by a CombiFlash® system using hexanes and ethyl acetate as eluent (from pure hexanes to pure ethyl acetate) to afford the title compound as a white solid.
