potassium superoxide; 18-crown-6 ether in dimethyl sulfoxide 1 h; Ambient temperature;

tert.-butyl lithium; 1,8-diazabicyclo[5.4.0]undec-7-ene 1.) toluene, r.t., 2 h; 2.) THF-pentane, -78 deg C, 1 h; Yield given. Multistep reaction;