1: 1.) TosOH*H2O, ethylene glycol, 2.) H2, 5percent Pd on charcoal / 1.) CH2Cl2, toluene, 1 h, reflux, 2.) AcOEt, 30 h, RT 2: N2O4, NaHCO3 / diethyl ether / 1 h / 0 °C 3: 1.) t-BuOK, 2.) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / 1.) THF, 1 h, -30 deg C, 2.) THF, 16 h, RT 4: 1.) LDA / 1.) THF, 30 min, -78 deg C, 2.) THF, 30 min, -78 deg C 5: 1.) MsCl, Et3N, 2.) Et3N / 1.) toluene, 2 h, RT, 2.) toluene, 48 h, reflux 6: 86 percent / pyridinium p-toluenesulfonate / acetone / 2 h / Heating View Scheme

Multi-step reaction with 3 steps 1: 1.) TosOH*H2O, ethylene glycol, 2.) H2, 5percent Pd on charcoal / 1.) CH2Cl2, toluene, 1 h, reflux, 2.) AcOEt, 30 h, RT2: N2O4, NaHCO3 / diethyl ether / 1 h / 0 °C3: 1.) t-BuOK, 2.) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / 1.) THF, 1 h, -30 deg C, 2.) THF, 16 h, RT  

Multi-step reaction with 5 steps 1: 1.) TosOH*H2O, ethylene glycol, 2.) H2, 5percent Pd on charcoal / 1.) CH2Cl2, toluene, 1 h, reflux, 2.) AcOEt, 30 h, RT2: N2O4, NaHCO3 / diethyl ether / 1 h / 0 °C3: 1.) t-BuOK, 2.) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / 1.) THF, 1 h, -30 deg C, 2.) THF, 16 h, RT4: 1.) LDA / 1.) THF, 30 min, -78 deg C, 2.) THF, 30 min, -78 deg C5: 1.) MsCl, Et3N, 2.) Et3N / 1.) toluene, 2 h, RT, 2.) toluene, 48 h, reflux