1: 73.5 percent / dimethylformamide / 1 h / 80 °C 2: 51 percent / 1,3-dimethyl-2-phenyl-1,3,2-diazaphospholidine / tetrahydrofuran / 1.) 0 deg C, 10 min, 2.) room temp., 3 h 3: 86 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.67 h / Ambient temperature 4: 0.57 g / H2 / 10percent Pd/C / methanol / 775.7 Torr View Scheme

K 10 clay in methanol; water T=75°C; 10 h;

1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 20 °C 2: trifluoroacetic acid / tetrahydrofuran; water / 3 h / 20 °C View Scheme