1: H2 / 5percent Pd/C / methanol / 1 h 2: concd. HCl / 0.67 h / Heating 3: 2.) N,N'-dicyclohexylcarbodiimide, TEA / 1.) 70 deg C, 7 h, 2.) 55 deg C, 5.5 h 4: H2 / 5percent Pd/C / methanol / 1 h / Ambient temperature 5: 1.) N,N'-carbonyldiimidazole / 1.) DMF, acetonitrile, r.t., 1.5 h, 2.) r.t., overnight 6: 74 percent / p-carboxybenzenesulfonyl azide, TEA / ethyl acetate / 0.5 h / Ambient temperature 7: 74 percent / Rh2(OAc)4 / benzene / 0.05 h / Heating 8: N,N-diisopropylethylamine / acetonitrile / 1.5 h / -20 °C View Scheme