n-butyllithium; boron trifluoride diethyl etherate in tetrahydrofuran; hexane T=-78°C;

n-butyllithium; boron trifluoride diethyl etherate 1.) 20 min, -78 deg C, THF/n-hexane; 2.) 30 min, -78 deg C, THF; Yield given. Multistep reaction;