1.1: 240 mg / DMAP / CH2Cl2 / 3 h / 20 °C 2.1: 75 percent / NaOMe / methanol / 2 h / Heating 3.1: 74 percent / H2 / 10 percent Pd/C / methanol / 0.07 h 4.1: oxalyl chloride; DMSO; DIPEA / CH2Cl2 / -78 - 20 °C 5.1: aq. HCl / CH2Cl2 / 0.5 h 6.1: LDA / tetrahydrofuran; hexane / 15 h / -78 °C 6.2: 77 percent / tetrahydrofuran; hexane / -78 - 20 °C View Scheme

Multi-step reaction with 3 steps 1: 240 mg / DMAP / CH2Cl2 / 3 h / 20 °C2: 75 percent / NaOMe / methanol / 2 h / Heating3: 74 percent / H2 / 10 percent Pd/C / methanol / 0.07 h  

Multi-step reaction with 3 steps 1: 87 percent / TFA; MCPBA / CH2Cl2 / 16 h / 0 - 5 °C2: 99 percent / aq. HCl / methanol / 2 h / Heating3: 98 percent / DIPEA / CH2Cl2 / 20 °C