1: toluene / 48 h / Heating 2: 0.1 N HCl / Ambient temperature 3: toluene / pH = 8.4; buffer: LiOH, 85percent aq. H3PO4, CH3COOH, B(OH)3 4: 70 percent / Red-Al, CuBr / tetrahydrofuran; benzene / 1.) -78 deg C -> -20 deg C, 10 min., 2.) -20 deg C, 1.5 h View Scheme