1: DIBAL-H / CH2Cl2 / 1.75 h / -78 °C 2: 0.190 g / KHMDS; 18-crown-6 / tetrahydrofuran; toluene / 4 h / -78 °C 3: 91 percent / DIBAL-H / diethyl ether; toluene / 1 h / -78 °C 4: 89 percent / Dess-Martin periodinane / CH2Cl2 / 2 h / 0 °C 5: 93 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene; lithium chloride / acetonitrile / 2 h / 0 °C 6: 82 percent / sodium borohydride; sulfur / tetrahydrofuran / 2 h / 65 °C 7: 85 percent / morpholine; tetrakis(triphenylphosphine)palladium(0) / tetrahydrofuran / 24 h 8: 78 percent / bis(2-oxo-3-oxazolidinyl)phosphinic chloride; diisopropylethylamine / toluene / 16.5 h / 85 °C 9: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 4.5 h / 0 - 20 °C 10: 95 percent / aq. HF / acetonitrile / 6 h / 20 °C 11: 5 percent / aq. HNO3; acetic acid / 0.02 h / 20 °C View Scheme