1: tBuOK / tetrahydrofuran / Ambient temperature 2: 9-BBN / tetrahydrofuran / 0 °C 3: 50percent aq. NaOH / Bu4N*HSO4 / CH2Cl2 / 40 °C 4: Bu4NF / tetrahydrofuran / Ambient temperature 5: SO3*Py, Et3N / dimethylsulfoxide / Ambient temperature 6: 90 percent / NaH / tetrahydrofuran / Ambient temperature 7: 100 percent / AcOH / tetrahydrofuran; H2O / 50 °C 8: 79 percent / diisobutylaluminum 2,6-di-t-butyl-4-methylphenoxide / toluene / -78 - -20 °C 9: 90 percent / 7percent aq. KOH / methanol View Scheme

Multi-step reaction with 3 steps 1: tBuOK / tetrahydrofuran / Ambient temperature2: 9-BBN / tetrahydrofuran / 0 °C3: 50percent aq. NaOH / Bu4N*HSO4 / CH2Cl2 / 40 °C