1: sodium borohydride / ethanol / 2 h / Heating 2: 1.) BF3*O(C2H5)2 / 1.) room temp., 5 min, 2.) reflux, 15 h View Scheme

boron trifluoride diethyl etherate 1.) room temp., 5 min, 2.) reflux, 15 h; Yield given. Multistep reaction;