1: 1.) t-butyl-lithium, 2.) zinc bromide / 3.) <Pd(PPh3)4> / 1.) ether, -78 deg C, 45 min, 2.) -20 deg C, 1 h, 3.) THF, reflux, 2.5 h 2: tetrabutylammonium fluoride / tetrahydrofuran / 0.17 h / Heating 3: various solvent(s) / 5 h / Heating 4: 75 percent / chromium trioxide, celite / CH2Cl2; diethyl ether / 0 deg C, 20 deg C, 1.5 h View Scheme

Multi-step reaction with 2 steps 1: 1.) t-butyl-lithium, 2.) zinc bromide / 3.) <Pd(PPh3)4> / 1.) ether, -78 deg C, 45 min, 2.) -20 deg C, 1 h, 3.) THF, reflux, 2.5 h2: tetrabutylammonium fluoride / tetrahydrofuran / 0.17 h / Heating