1: With n-butyllithium; N-ethyl-N,N-diisopropylamine in tetrahydrofuran T=-78°C; 0.5 h; 2: With [TiCl(isopropoxy)3] in tetrahydrofuran; hexane T=-30°C; 2 h; 3: With benzaldehyde in tetrahydrofuran; hexane T=-40°C; 2 h; Further stages.;

1.1: 76 percent / lithium hydroxide; hydrogen peroxide / tetrahydrofuran; H2O / 4 h / 20 °C 2.1: diisopropylamine; n-butyllithium / tetrahydrofuran; hexane / 1.25 h / -78 - -40 °C 2.2: 59 percent / ZnCl2 / tetrahydrofuran; hexane; diethyl ether / 0.25 h / -78 °C 3.1: pyridine / CH2Cl2 / 1 h / 0 °C 4.1: CH2Cl2 / 5 h / 20 °C 5.1: 0.67 g / acetic acid / tetrahydrofuran; H2O / 3 h / 0 °C 6.1: 72 percent / magnesium bromide; nitromethane; 1-butanethiol / diethyl ether / 1 h / 20 °C 7.1: 2,4,6-trichlorobenzoyl chloride; triethylamine / tetrahydrofuran / 1 h / 0 °C 7.2: 0.14 g / DMAP / toluene; tetrahydrofuran / 4 h / 20 °C 8.1: 92 percent / zinc; ammonium chloride / methanol / 0.33 h / Heating 9.1: 95 percent / hydrogen fluoride-pyridine / tetrahydrofuran / 16 h / 20 °C 10.1: 30 percent / m-CPBA / CHCl3 / 5 h / -10 - 0 °C View Scheme

1.1: 76 percent / lithium hydroxide; hydrogen peroxide / tetrahydrofuran; H2O / 4 h / 20 °C 2.1: diisopropylamine; n-butyllithium / tetrahydrofuran; hexane / 1.25 h / -78 - -40 °C 2.2: 59 percent / ZnCl2 / tetrahydrofuran; hexane; diethyl ether / 0.25 h / -78 °C 3.1: pyridine / CH2Cl2 / 1 h / 0 °C 4.1: CH2Cl2 / 5 h / 20 °C 5.1: 0.67 g / acetic acid / tetrahydrofuran; H2O / 3 h / 0 °C 6.1: 72 percent / magnesium bromide; nitromethane; 1-butanethiol / diethyl ether / 1 h / 20 °C 7.1: 2,4,6-trichlorobenzoyl chloride; triethylamine / tetrahydrofuran / 1 h / 0 °C 7.2: 0.14 g / DMAP / toluene; tetrahydrofuran / 4 h / 20 °C 8.1: 92 percent / zinc; ammonium chloride / methanol / 0.33 h / Heating 9.1: 95 percent / hydrogen fluoride-pyridine / tetrahydrofuran / 16 h / 20 °C View Scheme

1.1: TiCl4; iPr2NEt / CH2Cl2 / 1 h / -78 °C 1.2: 85 percent / CH2Cl2 / -78 - 0 °C 2.1: 72 percent / 2,6-lutidine / CH2Cl2 / 3.5 h / 0 °C 3.1: 30 percent / LiOH; H2O2 / tetrahydrofuran; H2O / 84 h / 20 °C View Scheme

1: 76 percent / lithium hydroxide; hydrogen peroxide / tetrahydrofuran; H2O / 4 h / 20 °C 2: 71 percent / borane-dimethyl sulfide; trimethyl borate / tetrahydrofuran / 9 h / 0 - 15 °C 3: 72 percent / imidazole / CH2Cl2 / 3 h / 0 °C View Scheme