1: With n-butyllithium; 1,1-dibromomethane in tetrahydrofuran; hexane T=20°C; 2 h; Cooling with acetone-dry iceInert atmosphere; 2: With dihydrogen peroxide; sodium hydroxide in tetrahydrofuran; hexane; water T=0 - 20°C;

2: 91 percent Chromat. / red HgO, BF3*OEt2, H2O / tetrahydrofuran / 0.25 h / Heating View Scheme

Yield given. Multistep reaction;