1: 1.) oxalyl chloride, DMSO, 2.) triethylamine / 1.) CH2Cl2, - 78 deg C, 30 min, 2.) CH2Cl2, from - 78 deg C to RT 2: 950 mg / n-butyl lithium / tetrahydrofuran; hexane / 4 h / 0 °C 3: 9 percent HCl-MeOH / 3 h / Ambient temperature View Scheme

1: Swern oxidation 2: n-BuLi / tetrahydrofuran / -78 - 0 °C 3: HCl / methanol 4: 100 percent / H2 View Scheme