1: With 2,2,6,6-tetramethylpiperidinyl-lithium in tetrahydrofuran T=-78°C; 1 h; 2: With boric acid trimethyl ester in tetrahydrofuran T=-78°C; 2 h; 3: With dihydrogen peroxide; ammonium chloride in tetrahydrofuran; diethyl ether; water

1.1: phosphorus oxybromide / 4 h / 105 °C 2.1: lithium 2,2,6,6-tetramethylpiperidide / tetrahydrofuran / 1 h / -78 °C 2.2: trimethyl borate / tetrahydrofuran / 2 h / -78 °C 2.3: H2O2; NH4Cl / tetrahydrofuran; diethyl ether; H2O View Scheme