Multi-step reaction with 4 steps 1: 1) LDA / 1) THF, -78 deg C, 1 h, 2) -78 to 25 deg C, 3 h2: 1) LiAlH4, 2) CuCl2-CuO / 2) aq. acetone (4percent v/v)3: 74 percent / MeCu-DIBAH / tetrahydrofuran; hexamethylphosphoric acid triamide / -50 °C4: 74 percent / CuCl2 / dimethylformamide