1: 62 percent Spectr. / CH2Cl2 / 3 h / Heating 2: 73 percent Chromat. / DBU / toluene / 1 h / 20 °C View Scheme

1: 70 percent / NaN(SiMe3)2 / tetrahydrofuran / -78 °C 2: 1.) DIBAH; 2.) DMAP, Et3N / 1.) CH2Cl2, -78 degC; 2.) CH2Cl2 3: ZnBr2 / CH2Cl2 / from -45 degC to 0 degC 4: 1.) KOH; 2.) Li / 1.) dioxane, MeOH; 2.) NH3, THF, t-BuOH View Scheme