1: TBHP, D(-)DIPT,Ti(OiPr)4, 3A molecular sieves / CH2Cl2 / 3 h / -21 °C 2: imidazole / dimethylformamide 3: 1.) nBu3SnH, LDA, 2.) I2 / 1.) THF, 0 deg C, 3 h; 2.) Et2O, 0 deg C, 30 min 4: 1.) disiamylborane, 2.) aq. 2N NaOH, Pd(PPh3)4 / 1.) THF,0 deg C, 1h; 2.) 50 deg C, 16 h 5: 80 percent / nBu4NF / tetrahydrofuran / 18 h / 25 °C View Scheme

Multi-step reaction with 3 steps 1: TBHP, D(-)DIPT,Ti(OiPr)4, 3A molecular sieves / CH2Cl2 / 3 h / -21 °C2: imidazole / dimethylformamide3: 1.) nBu3SnH, LDA, 2.) I2 / 1.) THF, 0 deg C, 3 h; 2.) Et2O, 0 deg C, 30 min  

Multi-step reaction with 4 steps 1: TBHP, D(-)DIPT,Ti(OiPr)4, 3A molecular sieves / CH2Cl2 / 3 h / -21 °C2: imidazole / dimethylformamide3: 1.) nBu3SnH, LDA, 2.) I2 / 1.) THF, 0 deg C, 3 h; 2.) Et2O, 0 deg C, 30 min4: 1.) disiamylborane, 2.) aq. 2N NaOH, Pd(PPh3)4 / 1.) THF,0 deg C, 1h; 2.) 50 deg C, 16 h  

With  titanium(IV) isopropylate; tert.-butylhydroperoxide; 4 A molecular sieve; D-(-)-diisopropyl tartrate in  dichloromethane T=-21°C; 4 h;