2: 85 percent / n-butyl lithium / hexane; tetrahydrofuran / a) -78 deg C, 30 min, b) -70 deg C, 2 h, c) to r.t., 2 h 3: 86 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 1 h / Ambient temperature View Scheme