1: Et3N, SO3-C5H5N, DMSO / 0.08 h / Ambient temperature 2: CH2Cl2 / 6 h / Heating 3: 89 percent / DIBAL-H / toluene; hexane / 0.5 h / -78 °C 4: Et3N, SO3-C5H5N, DMSO / Ambient temperature 5: CH2Cl2 / 24 h / Heating 6: 80 percent / aq. LiOH / methanol / 12 h / 45 °C 7: 34 percent / DDQ / dioxane / 0.08 h / Ambient temperature 8: 33 percent / Et3N, ClCOOEt / tetrahydrofuran / 0.08 h / 0 °C 9: 81 percent / Amberlyst 15 / methanol / 1 h / 45 °C View Scheme

Multi-step reaction with 2 steps 1: Et3N, SO3-C5H5N, DMSO / 0.08 h / Ambient temperature2: CH2Cl2 / 6 h / Heating  

Multi-step reaction with 3 steps 1: Et3N, SO3-C5H5N, DMSO / 0.08 h / Ambient temperature2: CH2Cl2 / 6 h / Heating3: 89 percent / DIBAL-H / toluene; hexane / 0.5 h / -78 °C  

Multi-step reaction with 4 steps 1: Et3N, SO3-C5H5N, DMSO / 0.08 h / Ambient temperature2: CH2Cl2 / 6 h / Heating3: 89 percent / DIBAL-H / toluene; hexane / 0.5 h / -78 °C4: Et3N, SO3-C5H5N, DMSO / Ambient temperature  

Multi-step reaction with 5 steps 1: Et3N, SO3-C5H5N, DMSO / 0.08 h / Ambient temperature2: CH2Cl2 / 6 h / Heating3: 89 percent / DIBAL-H / toluene; hexane / 0.5 h / -78 °C4: Et3N, SO3-C5H5N, DMSO / Ambient temperature5: CH2Cl2 / 24 h / Heating  

Multi-step reaction with 6 steps 1: Et3N, SO3-C5H5N, DMSO / 0.08 h / Ambient temperature2: CH2Cl2 / 6 h / Heating3: 89 percent / DIBAL-H / toluene; hexane / 0.5 h / -78 °C4: Et3N, SO3-C5H5N, DMSO / Ambient temperature5: CH2Cl2 / 24 h / Heating6: 80 percent / aq. LiOH / methanol / 12 h / 45 °C