1: 91 percent / DIPEA, DMAP / CH2Cl2 / 0.67 h / -78 °C 2: 95 percent / K2CO3 / methanol / 2 h 3: 90 percent / Dess-Martin reagent / CH2Cl2 4: 41 percent / L-Selectride / tetrahydrofuran / -78 - 20 °C View Scheme

1: 91 percent / DIPEA, DMAP / CH2Cl2 / 0.67 h / -78 °C 2: 95 percent / K2CO3 / methanol / 2 h 3: 90 percent / Dess-Martin reagent / CH2Cl2 View Scheme