1.1: 75 percent / KOH / Heating 2.1: diisopropyl amine; n-butyllithium; triethylamine / chlorotrimethylsilane / tetrahydrofuran; petroleum ether / -78 - 0 °C 2.2: bromine / tetrahydrofuran; petroleum ether / 2 h / -78 °C 3.1: 5.0 g / lithium carbonate; lithium bromide / dimethylformamide / 4 h / 100 - 105 °C 4.1: diisopropyl amine; n-butyllithium / diethyl ether; petroleum ether / 0.58 h / -78 °C 4.2: diethyl ether; petroleum ether / 1 h / -78 °C 5.1: 378 mg / triethylamine; methanesulfonyl chloride / CH2Cl2 / 4 h / 20 °C 6.1: lithium chloride / tetrahydrofuran / 2 h / 20 °C 6.2: n-butyllithium / tetrahydrofuran; petroleum ether / 0.08 h / -78 °C 6.3: 70 percent / tetrahydrofuran; petroleum ether / 0.5 h / -78 °C 7.1: 91 percent / PCC / CH2Cl2 / 48 h / 20 °C 8.1: cerium trichloride; sodium borohydride / methanol / 0.5 h / 0 °C 9.1: 173 mg / mCPBA / CH2Cl2 / 1 h / 0 °C 10.1: 86 percent / Dess-Martin periodonane; sodium bicarbonate / CH2Cl2 / 1 h / 20 °C 11.1: magnesium bromide diethyl etherate / CH2Cl2 / 12 h / -78 °C 12.1: 1.0 g / pyridine; trifluoroacetic anhydride; triethylamine / CH2Cl2 / 3.5 h / 0 - 20 °C 13.1: magnesium bromide diethyl etherate; butanethiol / diethyl ether / 15 h / 20 °C 13.2: 77 percent / camphorsulfonic acid / CH2Cl2 / 18 h / 20 °C 14.1: 94 percent / cerium trichloride; sodium borohydride / methanol / 0.5 h / 0 °C 15.1: triphenylphosphine; diethyl azodicarboxylate; 4-nitrobenzoic acid / tetrahydrofuran / 12 h / 20 °C 15.2: 86 percent / sodium methoxide / methanol / 1 h / 20 °C 16.1: 92 percent / imidazole / dimethylformamide / 2 h / 40 °C 17.1: t-butyllithium / diethyl ether; pentane / 0.5 h / -78 °C 17.2: 51 percent / TMEDA / diethyl ether; pentane / 0.08 h / -78 °C 18.1: 90 percent / Dess-Martin periodinane; sodium bicarbonate / CH2Cl2 / 1 h / 20 °C 19.1: TBAF / tetrahydrofuran / 0.5 h / 0 °C 20.1: 25 mg / HCl / 2-methyl-butan-2-ol / 2 h / 20 °C 21.1: 83 percent / imidazole / dimethylformamide / 2 h / 20 °C 22.1: 87 percent / DDQ / CH2Cl2; H2O / 0.5 h / 20 °C 23.1: 81 percent / pyridine / CH2Cl2 / 0.17 h / -78 °C 24.1: 9-BBN / tetrahydrofuran / 2 h / 40 °C 24.2: 37 percent / thallium carbonate; triphenylarsine / [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) / tetrahydrofuran; dimethylformamide; H2O / 12 h / 20 °C 25.1: 78 percent / TBAF / tetrahydrofuran / 0.5 h / 0 °C View Scheme