1.1: CrO3; 3,5-dimethylpyrazole / CH2Cl2 / 0.33 h / -20 - -10 °C 2.1: ozone / CH2Cl2; methanol / -78 - 20 °C 2.2: 93 percent / dimethyl sulfide / CH2Cl2; methanol / 3 h / 20 °C 3.1: 96 percent / trimethylsilyl triflate / CH2Cl2 / 16 h / -78 °C 4.1: sodium naphthalenide / tetrahydrofuran / -25 °C 4.2: 82 percent / triethylamine / tetrahydrofuran / 4 h / -25 - 20 °C 5.1: Rose Bengal; oxygen / tetradeuteriomethanol / 0.5 h / Irradiation; acetone/dry ice cooling 6.1: TMSOTf / CH2Cl2 / 0.33 h / -78 °C 6.2: 1.39 mg / water; CSA / CH2Cl2 / 3 h / 20 °C View Scheme