1: 95 percent / diisobutylaluminium hydride / CH2Cl2 2: DMAP, Et3N / CH2Cl2 / 0.5 h / 0 °C 3: LiCl / dimethylformamide / 0.5 h / 0 °C 5: O2, rose bengal / CH2Cl2; methanol / -78 °C / Irradiation 6: 2N hydrochloric acid / tetrahydrofuran / 2 h / Ambient temperature 7: Irradiation View Scheme