1: 87 percent / DMAP / pyridine / 1.) 0 deg C -> 25 deg C, 1 h, 2.) 25 deg C, 48 h 2: 71 percent / LiCl, 4A sieves, Me4Sn, 2,6-di-tert-butylhydroxytoluene / PdCl2(dppf) / dimethylformamide / 12 h / 90 °C / 2585.7 Torr 3: 1.) LiHMDS, 2,2,2-trifluoroethyl trifluoroacetate, 2.) MsN3, Et3N / 1.) THF, -78 deg C, 45 min, 2.) MeCN, H2O, 25 deg C, 6 h 4: 64 percent / benzene / 24 h / Ambient temperature; Irradiation 5: 84 percent / n-Bu4NF, O2 / tetrahydrofuran / 40 h / 25 °C View Scheme

1: 87 percent / DMAP / pyridine / 1.) 0 deg C -> 25 deg C, 1 h, 2.) 25 deg C, 48 h 2: 71 percent / LiCl, 4A sieves, Me4Sn, 2,6-di-tert-butylhydroxytoluene / PdCl2(dppf) / dimethylformamide / 12 h / 90 °C / 2585.7 Torr 3: 1.) LiHMDS, 2,2,2-trifluoroethyl trifluoroacetate, 2.) MsN3, Et3N / 1.) THF, -78 deg C, 45 min, 2.) MeCN, H2O, 25 deg C, 6 h 4: 64 percent / benzene / 24 h / Ambient temperature; Irradiation 5: 84 percent / n-Bu4NF, O2 / tetrahydrofuran / 40 h / 25 °C 6: 100 percent / conc. H2SO4 / ethanol / 0.75 h / 25 °C View Scheme

1: 87 percent / DMAP / pyridine / 1.) 0 deg C -> 25 deg C, 1 h, 2.) 25 deg C, 48 h 2: 71 percent / LiCl, 4A sieves, Me4Sn, 2,6-di-tert-butylhydroxytoluene / PdCl2(dppf) / dimethylformamide / 12 h / 90 °C / 2585.7 Torr 3: 1.) LiHMDS, 2,2,2-trifluoroethyl trifluoroacetate, 2.) MsN3, Et3N / 1.) THF, -78 deg C, 45 min, 2.) MeCN, H2O, 25 deg C, 6 h 4: 64 percent / benzene / 24 h / Ambient temperature; Irradiation 5: 84 percent / n-Bu4NF, O2 / tetrahydrofuran / 40 h / 25 °C 6: 100 percent / conc. H2SO4 / ethanol / 0.75 h / 25 °C 7: 91 percent / DDQ / benzene / 42 h / 25 °C View Scheme