potassium fluoride; selenium; n-butyllithium; acetic acid 1.) ether, hexane, 2.) ether, hexane, -78 deg C, 5 min, 3.) room temperature, 1 h; Yield given. Multistep reaction;

(i) EtMgBr, Et2O, (ii) /BRN= 2232609/; Multistep reaction;