1.1: 81 percent / Fe(acac)3 / tetrahydrofuran; 1-methyl-pyrrolidin-2-one / 1 h / 0 °C 2.1: aq. HCl / tetrahydrofuran / 1.5 h / 70 °C 3.1: n-BuLi / tetrahydrofuran; hexamethylphosphoric acid triamide; hexane / 1 h / -78 °C 3.2: 3.16 g / tetrahydrofuran; hexamethylphosphoric acid triamide; hexane / 2.5 h / -78 - 20 °C 4.1: disiamylborane / tetrahydrofuran / 4.25 h / -20 - 0 °C 4.2: 76 percent / glacial acetic acid / tetrahydrofuran / 20 °C 5.1: 90 percent / triphenylphosphine dibromide / CH2Cl2 / 1.5 h / 20 °C 6.1: Li / diethyl ether / 2 h / 0 °C 6.2: 34 percent / diethyl ether / 2 h / -20 °C View Scheme

diisoamyl borane; acetic acid 1.) THF, -10 deg C, 90 min, 2.) 55 deg C, 1 h; Yield given. Multistep reaction;