1: water / acetone / 1 h 2: hydrazine / ethanol / 3 h / 0 - 23 °C View Scheme

1: KOt-Bu / tetrahydrofuran 2: aq. HCl, CH2Cl2 3: 66 percent / NaOMe, MeOH / tetrahydrofuran / 5 °C 4: 55 percent / xylene / Heating 5: 80 percent / sodium cyanoborohydride / acetic acid 6: 70 percent / DIBAL / toluene / -70 °C 7: 51 percent / Ph2P(CH3)2PPh2 / (Ph3P)Rh(CO)Cl / xylene / Heating View Scheme

Multi-step reaction with 2 steps 1: KOt-Bu / tetrahydrofuran2: aq. HCl, CH2Cl2  

Multi-step reaction with 3 steps 1: KOt-Bu / tetrahydrofuran2: aq. HCl, CH2Cl2 3: 66 percent / NaOMe, MeOH / tetrahydrofuran / 5 °C  

Multi-step reaction with 5 steps 1: KOt-Bu / tetrahydrofuran2: aq. HCl, CH2Cl2 3: 66 percent / NaOMe, MeOH / tetrahydrofuran / 5 °C4: 55 percent / xylene / Heating5: sodium cyanoborohydride / acetic acid  

Multi-step reaction with 4 steps 1: KOt-Bu / tetrahydrofuran2: aq. HCl, CH2Cl2 3: 66 percent / NaOMe, MeOH / tetrahydrofuran / 5 °C4: 55 percent / xylene / Heating