1.1: LiHMDS / tetrahydrofuran / -78 °C 1.2: lithium tert-butyl peroxide / tetrahydrofuran; toluene / 2.5 h / -78 - 0 °C 1.3: 99 percent / tetrahydrofuran; toluene / 0.5 h / 0 °C 2.1: 88 percent / HNTf2 / CH2Cl2 / 2 h / 20 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; petroleum ether / 1.5 h / 20 °C 1.2: MgBr2 / tetrahydrofuran; petroleum ether / 0.5 h / 20 °C 1.3: tetrahydrofuran; petroleum ether / 20 °C 2.1: aq. NaOH / methanol; tetrahydrofuran View Scheme