1: 1,1'-carbonyldiimidazole / acetonitrile 2: hydrogenchloride; water / ethyl acetate 3: triethylamine / ethyl acetate; toluene 4: dirhodium(II) tetraoctanoate / acetone / Reflux 5: N-ethyl-N,N-diisopropylamine; zinc(II) iodide / acetone / -30 °C 6: N-ethyl-N,N-diisopropylamine / 1-methyl-pyrrolidin-2-one / -25 °C 7: hydrogen / palladium on activated charcoal / ethyl acetate; water / 3-(N-morpholino)propanesulfonic acid buffer View Scheme

1: 1,1'-carbonyldiimidazole / acetonitrile 2: hydrogenchloride; water / ethyl acetate 3: triethylamine / ethyl acetate; toluene 4: dirhodium(II) tetraoctanoate / acetone / Reflux 5: N-ethyl-N,N-diisopropylamine; zinc(II) iodide / acetone / -30 °C View Scheme

1: 90 percent / K2CO3 / acetone / 4 h / Heating 2: 100 percent / NaH / tetrahydrofuran / 2 h / 0 °C 3: 100 percent / H2 / 10percent Pd/C / ethanol / 760 Torr / Ambient temperature 4: Et3N / CH2Cl2 / 1 h 5: CH2Cl2 / 1 h 6: 86 percent / anisole, TiCl4 / CH2Cl2 / 1 h / 0 °C 7: 93 percent / γ-collidine / dimethylformamide / 1.5 h / 65 °C 8: 98 percent / Et3N / toluene / 5 h / Ambient temperature 9: 1.) NaH, 2.) benzyl bromide / 1.) THF, toluene, -20 deg C, 1 h, 2.) THF, toluene, -20 deg C, 2 h 10: DBU / toluene; tetrahydrofuran / 2 h 11: 89 percent / phosphate buffer pH 3 / 2.5 h / Ambient temperature View Scheme

1.1: CDI / acetonitrile / 1 h / 20 °C 1.2: 86 percent / acetonitrile / 15 h / 20 °C 2.1: 90 percent / boron trifluoride diethyl etherate / acetonitrile / 3 h / 20 °C 3.1: 89 percent / Et3N / dimethylformamide / 2 h / 0 °C 4.1: Et3N / CH2Cl2 / 0.25 h / 0 °C 5.1: Et3N / CH2Cl2 / 0.5 h / -20 °C 6.1: toluene / 0.5 h / 20 °C 7.1: 1,3,5-trimethyl-benzene / 3 h / Heating 8.1: 88 percent / 1N aq. HCl / acetonitrile / 0.08 h / 0 °C View Scheme