hydrogenchloride; sodium periodate in tetrahydrofuran T=20°C; 4 h;

1: potassium carbonate / methanol / 1 h / 0 - 20 °C 2: 1.34 g / aq. sodium periodinate / methanol / 0 °C View Scheme

1.1: NBS / tetrahydrofuran; H2O 1.2: 62 percent / K2CO3 / methanol 2.1: 78 percent / NaIO4; aq. HCl / tetrahydrofuran / 4 h / 20 °C View Scheme

1: 3,5-dibromo-4-(di-tert-butyl(nonaprenyloxy)silyloxy)benzoic acid With 1,1'-carbonyldiimidazole in dichloromethane T=23°C; 0.5 h; 2: With dihydrogen peroxide in dichloromethane T=-78 - -20°C; 3: diazomethane With tetrabutylammonium (meta)periodate; pyridine hydrogenfluoride; periodic acid in tetrahydrofuran; diethyl ether; dichloromethane; water Further stages;

methanol; potassium carbonate T=20°C; 1 h;

pyridine; toluene-4-sulfonic acid in acetone 2 h; Heating;

1: 92.6 percent / diisobutylaluminum hydride / toluene; diethyl ether / a) -75 deg C, 1 h, b) -10 deg C, 0.5 h 2: aq. TsOH, pyridine / acetone / 2 h / Heating View Scheme