1.1: 88 percent / NaI / acetone / 12 h / Heating 2.1: NaH / tetrahydrofuran / 0.5 h / 20 °C 2.2: 80 percent / tetrahydrofuran; dimethylformamide / 18 h / Heating 3.1: 18-crown-6; 1-heptene; t-BuOK / Pd(OAc)2; 1,2-bis(diphenylphosphino)ethane / 1-methyl-pyrrolidin-2-one / 24 h / 60 °C 4.1: O3 / CH2Cl2 / -78 °C 4.2: dimethylsulfide / CH2Cl2 / -78 - 25 °C View Scheme