1: 1.) 1,8-diazabicyclo<5.4.0>ndec-7-ene (DBU); 2.) 3 N aq. HCl / 1.) DMSO, 80 deg C, 11 h; 2.) methanol, 30 min. 2: NaBH4 / CeCl3*7H2O / methanol / 0 °C View Scheme

1: 1.) 1,8-diazabicyclo<5.4.0>ndec-7-ene (DBU); 2.) 3 N aq. HCl / 1.) DMSO, 80 deg C, 11 h; 2.) methanol, 30 min. 2: NaBH4 / CeCl3*7H2O / methanol / 0 °C 3: 70 percent / trimethylsilyl triflate / CH2Cl2 / 3 h / -78 °C View Scheme

1: 1.) 1,8-diazabicyclo<5.4.0>ndec-7-ene (DBU); 2.) 3 N aq. HCl / 1.) DMSO, 80 deg C, 11 h; 2.) methanol, 30 min. 2: NaBH4 / CeCl3*7H2O / methanol / 0 °C 3: 67 percent / pyridinim p-toluenesulfonate (PPTS) / 1.5 h / Ambient temperature; further catalyst View Scheme

1: 1.) 1,8-diazabicyclo<5.4.0>ndec-7-ene (DBU); 2.) 3 N aq. HCl / 1.) DMSO, 80 deg C, 11 h; 2.) methanol, 30 min. 2: NaBH4 / CeCl3*7H2O / methanol / 0 °C 3: 46 percent / pyridinium p-toluenesulfonate (PPTS) / 1.5 h / Ambient temperature; further catalyst View Scheme

hydrogenchloride; 1,8-diazabicyclo[5.4.0]undec-7-ene 1.) DMSO, 80 deg C, 11 h; 2.) methanol, 30 min.; Yield given. Multistep reaction;