1: 47 percent / N-bromo-succinimide dibenzoyl peroxide / CCl4 / 0.33 h / Heating 2: t-BuOK / tetrahydrofuran / -78 - -35 °C 3: 43 percent / conc. HCl / 15 h / from -78 deg C to r.t. View Scheme

1: 47 percent / N-bromo-succinimide dibenzoyl peroxide / CCl4 / 0.33 h / Heating 2: t-BuOK / tetrahydrofuran / -78 - -35 °C 3: 20 percent / conc. HCl / 15 h / from -78 deg C to r.t. View Scheme