1: 99 percent / DMSO, (COCl)2, Et3N / CH2Cl2 2: Ph3P / CH2Cl2 / -78 °C 3: LDA / tetrahydrofuran / -30 °C 4: 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: 23 percent / (C6H11)2NMgBr / tetrahydrofuran / -55 °C 9: 95 percent / DDQ / CH2Cl2; H2O / 0.17 h / Ambient temperature 10: 70 percent / TFA, molecular sieves / CH2Cl2 View Scheme

 Yield given. Multistep reaction;   

Multi-step reaction with 8 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 °C4: 1) DMSO, (COCl2)2, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 to -15 deg C5: 96 percent / Ph3P / benzene / 0.5 h / 80 °C6: 84 percent / n-BuLi / hexane; tetrahydrofuran / -78 - -20 °C7: 1) NaH / 1) DMF, 2) DMF, 50 deg C, 2 h8: MeOH, CSA / 0.25 h / Ambient temperature  

Multi-step reaction with 4 steps 1: 96 percent / Ph3P / benzene / 0.5 h / 80 °C2: 84 percent / n-BuLi / hexane; tetrahydrofuran / -78 - -20 °C3: 1) NaH / 1) DMF, 2) DMF, 50 deg C, 2 h4: MeOH, CSA / 0.25 h / Ambient temperature  

Multi-step reaction with 2 steps 1: 1) NaH / 1) DMF, 2) DMF, 50 deg C, 2 h2: MeOH, CSA / 0.25 h / Ambient temperature  

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: 88 percent / Ph3P / CH2Cl2 / 0.33 h / -78 °C3: 83 percent / LDA / tetrahydrofuran / 0.67 h / -70 °C  

Multi-step reaction with 7 steps 1: 99 percent / DMSO, (COCl)2, Et3N / CH2Cl2 2: Ph3P / CH2Cl2 / -78 °C3: LDA / tetrahydrofuran / -30 °C4: 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 temperature