1.1: 92 percent / LDA / tetrahydrofuran / 20 °C 2.1: n-BuLi / tetrahydrofuran; hexane / 0.08 h / 0 °C 2.2: 71 percent / tetrahydrofuran / -40 - 20 °C 3.1: 93 percent / aq. HCO2H; Pd(OAc)2; Ph3P / dimethylformamide / 60 - 70 °C 4.1: 91 percent / BBr3 / CH2Cl2 / -78 - 20 °C View Scheme

1.1: 92 percent / LDA / tetrahydrofuran / 20 °C 2.1: n-BuLi / tetrahydrofuran; hexane / 0.08 h / 0 °C 2.2: 71 percent / tetrahydrofuran / -40 - 20 °C 3.1: 93 percent / aq. HCO2H; Pd(OAc)2; Ph3P / dimethylformamide / 60 - 70 °C View Scheme

1.1: 92 percent / LDA / tetrahydrofuran / 20 °C 2.1: 99 percent / O2; salcomine / dimethylformamide / 4 h / 20 °C 3.1: aq. KOH / 1 h / 90 °C 3.2: 99 percent / Pb(OAc)4 / benzene / 20 °C View Scheme

With  lithium diisopropyl amide in  tetrahydrofuran  0 deg C to rt, 3 h;