1: DIBAL-H 2: 92 percent / BuLi, Ph3CH, p-TsCl, LiCl / hexamethylphosphoric acid triamide; hexane; diethyl ether / Ambient temperature 3: 1.) EtMgBr; 2.) 5percent CH3COOH / 1.) THF, 24 h, r.t.; 2.) 0 deg C, THF/H2O 4: 80 percent / NaH / dimethylsulfoxide / 3 h / 60 °C 5: 98 percent / acetone, p-TsOH / Heating View Scheme

1: DIBAL-H 2: 92 percent / BuLi, Ph3CH, p-TsCl, LiCl / hexamethylphosphoric acid triamide; hexane; diethyl ether / Ambient temperature 3: 1.) EtMgBr; 2.) 5percent CH3COOH / 1.) THF, 24 h, r.t.; 2.) 0 deg C, THF/H2O View Scheme