1: Al(Hg) / tetrahydrofuran; H2O 2: 94 percent / pyridine / tetrahydrofuran / Heating 3: 1.) n-BuLi, TMEDA, 2.) DMF 4: 1.) Et2O, pentane, -78 deg C, 2.) DMAP, 20 deg C 5: 56 percent / LICA / tetrahydrofuran / -78 deg C to 20 deg C 6: 94 percent / K2CO3 / acetone 7: 1.) LICA / 1.) THF, 0 deg C, 2.) 0 deg C 8: 1.) KOH, 2.) aq. oxalic acid, silicagel / 1.) MeOH, 2.) CH2Cl2, 20 deg C 9: 1.) O3, 2.) CF3COOH / 1.) MeOH, -78 deg C, 2.) CHCl3, H2O View Scheme

Multi-step reaction with 3 steps 1: 1.) NaH / 1.) THF, RT, 30 min, 2.) THF, reflux, 24 h2: 95 percent / m-CPBA / CH2Cl2 / -78 °C3: 1.) LDA, HMPT / 1.) THF, hexane, -35 deg C, 3 h, 2.) THF, hexane, from -35 deg C to RT, 2 h