in tetrahydrofuran; diethyl ether T=-78 - 0°C; 1 h;

bromine; potassium carbonate in chloroform T=0°C; Bromination; retro-Barbier fragmentation; 5 h;

1: 72 percent / HBr / benzene / 18 h / Heating 2: 80 percent / Jones reagent / acetone / 1 h / 0 - 20 °C 3: 64 percent / tetrahydrofuran; diethyl ether / 1 h / -78 - 0 °C View Scheme

1: 80 percent / Jones reagent / acetone / 1 h / 0 - 20 °C 2: 64 percent / tetrahydrofuran; diethyl ether / 1 h / -78 - 0 °C View Scheme