camphor-10-sulfonic acid in benzene T=70°C; 1 h;

1: 90 percent / NaBH4, CeCl3*7H2O / methanol 2: 95 percent / Et3N / CH2Cl2 3: 85 percent / mCPBA / CH2Cl2 4: 90 percent / PTSA / methanol 5: 77 percent / LAH / tetrahydrofuran 6: 95 percent / Et3N / CH2Cl2 8: 88 percent / PTSA / benzene View Scheme

1: KOH / 2-methyl-propan-2-ol / 4 h / 70 °C 2: 98 percent / DMAP / CH2Cl2 / 1 h / 25 °C 3: 92 percent / CSA / benzene / 1 h / 70 °C View Scheme