1.1: 98 percent / OXONE; H2O / tetrahydrofuran / 12 h / 0 - 20 °C 2.1: 98 percent / TfOH / 2 h / 5 - 20 °C 3.1: BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 3.2: PhCOCl / tetrahydrofuran; hexane / 3 h / -78 - 20 °C 3.3: 60 percent / t-BuOK / tetrahydrofuran; hexane / 3 h / Heating 4.1: 82 percent / OXONE; H2O / tetrahydrofuran / 12 h / 0 - 20 °C View Scheme

1: 98 percent / OXONE; H2O / tetrahydrofuran / 12 h / 0 - 20 °C 2: 98 percent / TfOH / 2 h / 5 - 20 °C View Scheme

1.1: 98 percent / OXONE; H2O / tetrahydrofuran / 12 h / 0 - 20 °C 2.1: 98 percent / TfOH / 2 h / 5 - 20 °C 3.1: BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 3.2: PhCOCl / tetrahydrofuran; hexane / 3 h / -78 - 20 °C 3.3: 82 percent / t-BuOK / tetrahydrofuran; hexane / 3 h / Heating View Scheme

Oxonereg;; water in tetrahydrofuran T=0 - 20°C; Hydrolysis; oxidation; 12 h;

1.1: 98 percent / OXONE; H2O / tetrahydrofuran / 12 h / 0 - 20 °C 2.1: 98 percent / TfOH / 2 h / 5 - 20 °C 3.1: BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 3.2: PhCOCl / tetrahydrofuran; hexane / 3 h / -78 - 20 °C 3.3: 55 percent / t-BuOK / tetrahydrofuran; hexane / 3 h / Heating 4.1: 95 percent / OXONE; H2O / tetrahydrofuran / 12 h / 0 - 20 °C 5.1: 99 percent / TfOH / 2 h / 5 - 20 °C View Scheme