N,N,N',N'-tetramethylguanidine in acetonitrile T=50°C; 1 h;

1: 1.) BuLi / 1.) THF, hexane, 0 deg C, 15 min, 2.) THF, -78 deg C, 20 min 2: 90 percent / H2 / 5percent PdC / tetrahydrofuran; acetic acid / 21 h / 33602700 Torr / Ambient temperature 3: 89 percent / HOBT, DCC / tetrahydrofuran / 15 h / Ambient temperature 4: 73 percent / TBSOTf, 2,6-lutidine / CH2Cl2 / 2 h / 0 °C 5: DCC, HOBT / CH2Cl2 / 1.) -20 deg C, 30 min, 2.) 4 deg C, 40 h 78 percent 6: 78 percent / LiOH / H2O; tetrahydrofuran; methanol / 144 h / Ambient temperature 7: CMC, DMAP*TFA / CHCl3; tetrahydrofuran / 1.) 20 h, 2.) reflux, 1 h, 28 percent View Scheme