1: 99 percent / DMSO, (COCl)2, Et3N / CH2Cl2 2: 96 percent / PPh3 / benzene / 80 °C 3: 84 percent / n-BuLi / tetrahydrofuran / -78 °C 4: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) oxidation 5: 1.) camphorsulfonic acid, 2.) n-Bu4NF / 1.) room temperature, 2.) dioxane-THF, 65 deg C 6: 88 percent / H2 / Lindlar / methanol 7: 1.) DMSO,(COCl)2, Et3N, 2.) CSA / 1.) CH2Cl2, 2.) CH2Cl2, room temperature 8: (C6H11)2NMgBr / methanol / -55 °C 9: DDQ / CH2Cl2 / 1.5 h / Ambient temperature; buffer (pH 6.86) View Scheme

Multi-step reaction with 3 steps 1: 64 percent / pyridine / CH2Cl2 / 4 h / 0 °C2: 100 percent / Et3N / CH2Cl2 / 0.5 h / 0 °C3: 95 percent / aq. KOH / methanol / 0.5 h / 55 °C  

Multi-step reaction with 3 steps 1: 1) DMSO, (COCl2)2, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 to -15 deg C2: 96 percent / Ph3P / benzene / 0.5 h / 80 °C3: 84 percent / n-BuLi / hexane; tetrahydrofuran / -78 - -20 °C  

Multi-step reaction with 5 steps 1: 99 percent / DMSO, (COCl)2, Et3N / CH2Cl2 2: 96 percent / PPh3 / benzene / 80 °C3: 84 percent / n-BuLi / tetrahydrofuran / -78 °C4: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) oxidation5: 1.) camphorsulfonic acid, 2.) n-Bu4NF / 1.) room temperature, 2.) dioxane-THF, 65 deg C  

Multi-step reaction with 9 steps 1: 99 percent / DMSO, (COCl)2, Et3N / CH2Cl2 2: 96 percent / PPh3 / benzene / 80 °C3: 84 percent / n-BuLi / tetrahydrofuran / -78 °C4: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) oxidation5: 1.) camphorsulfonic acid, 2.) n-Bu4NF / 1.) room temperature, 2.) dioxane-THF, 65 deg C6: 88 percent / H2 / Lindlar / methanol7: 1.) DMSO,(COCl)2, Et3N, 2.) CSA / 1.) CH2Cl2, 2.) CH2Cl2, room temperature8: (C6H11)2NMgBr / methanol / -55 °C9: DDQ / CH2Cl2 / 1.5 h / Ambient temperature; buffer (pH 6.86)  

 Yield given. Multistep reaction;   

Multi-step reaction with 8 steps 1: 1) DMSO, (COCl2)2, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 to -15 deg C2: 96 percent / Ph3P / benzene / 0.5 h / 80 °C3: 84 percent / n-BuLi / hexane; tetrahydrofuran / -78 - -20 °C4: 1) NaH / 1) DMF, 2) DMF, 50 deg C, 2 h5: MeOH, CSA / 0.25 h / Ambient temperature6: 1) DMSO, (COCl2)2, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 to -15 deg C7: 88 percent / Ph3P / CH2Cl2 / 0.33 h / -78 °C8: 83 percent / LDA / tetrahydrofuran / 0.67 h / -70 °C  

Multi-step reaction with 8 steps 2: 99 percent / DMSO, (COCl)2, Et3N / CH2Cl2 3: Ph3P / CH2Cl2 / -78 °C4: LDA / tetrahydrofuran / -30 °C5: n-BuLi / 1.) THF, -78 deg C, 2.) oxidation6: 1.) camphorsulfonic acid, 2.) n-Bu4NF / 1.) room temperature, 2.) dioxane-THF, 65 deg C7: 88 percent / H2 / Lindlar / methanol8: 1.) DMSO, (COCl)2, Et3N, 2.) CSA / 1.) CH2Cl2, 2.) CH2Cl2, room temperature  

With  oxalyl dichloride; dimethyl sulfoxide; triethylamine in  dichloromethane