1.1: potassium tert-butoxide / tetrahydrofuran / 0 - 20 °C 1.2: 86 percent / tetrahydrofuran / 7 h / 0 - 20 °C 2.1: 99 percent / oxalyl chloride; DMSO; triethylamine / CH2Cl2 / -78 - 20 °C 3.1: 96 percent / tetrahydrofuran / 1 h / -78 °C 4.1: 95 percent / Neolyst dichlorideTM / CH2Cl2 / 48 h / 20 °C 5.1: 90 percent / pyridinium dichromate; 4 Angstroem molecular sieves / dimethylformamide / 48 h / 20 °C View Scheme

1.1: potassium tert-butoxide / tetrahydrofuran / 0 - 20 °C 1.2: 86 percent / tetrahydrofuran / 7 h / 0 - 20 °C 2.1: 99 percent / oxalyl chloride; DMSO; triethylamine / CH2Cl2 / -78 - 20 °C 3.1: 96 percent / tetrahydrofuran / 1 h / -78 °C 4.1: 95 percent / Neolyst dichlorideTM / CH2Cl2 / 48 h / 20 °C 5.1: 90 percent / pyridinium dichromate; 4 Angstroem molecular sieves / dimethylformamide / 48 h / 20 °C 6.1: 99 percent / sodium borohydride; cerium(III) chloride heptahydrate / methanol / 0.5 h / 0 - 5 °C 7.1: triphenylphosphine; DIAD / tetrahydrofuran / 0.67 h / 0 - 20 °C 7.2: 74 percent / tetrahydrofuran / 20 °C 8.1: 99 percent / TFA; MeOH / 1,2-dichloro-ethane / 20 °C View Scheme