N-bromosuccinmide; 2,2'-azo-bisisobutyronitrile in tetrachloromethane 12 h; Heating;

1: 67 percent / Et3N / benzene / 24 h / Heating 2: 56 percent / NBS / AIBN / CCl4 / 12 h / Heating View Scheme

1: 1) thionylchloride, 2) aqueous potassium hydroxide / 1) 0 deg C, 1 h, 2) reflux, 8 h. 2: 56 percent / nickel peroxide / benzene / 15 h / Heating 3: 56 percent / 1) bromine, 2) triethylamine / benzene / 7 h / Heating View Scheme

1: 77 percent / Heating 2: 1) thionylchloride, 2) aqueous potassium hydroxide / 1) 0 deg C, 1 h, 2) reflux, 8 h. 3: 56 percent / nickel peroxide / benzene / 15 h / Heating 4: 56 percent / 1) bromine, 2) triethylamine / benzene / 7 h / Heating View Scheme

ozone in dichloromethane T=-78°C; 1 h; variation of O3-concentration; also with 5-ethoxy-2-phenyloxazole or in MeOH or EtOH; Product distributionMechanism;

1: 5-bromo-2-phenyl-1,3-oxazole With n-butyllithium in tetrahydrofuran; hexane T=-80 - -50°C; Inert atmosphere; 2: With tributyltin chloride in tetrahydrofuran; hexane T=-80°C; Inert atmosphere; 3: iodobenzene With tetrakis(triphenylphosphine) palladium(0); cesium fluoride in toluene Stille cross-coupling reaction; RefluxInert atmosphere;

1: 5-bromo-2-phenyl-1,3-oxazole With n-butyllithium in tetrahydrofuran; hexane T=-80 - -50°C; Inert atmosphere; 2: With tributyltin chloride in tetrahydrofuran; hexane T=-80°C; Inert atmosphere; 3: (1,1,1-tributylstannyl)benzene With tetrakis(triphenylphosphine) palladium(0); cesium fluoride in toluene Stille cross-coupling reaction; RefluxInert atmosphere;

1: [PdCl2(PPh3)2] 2: 20 percent / Cs2CO3; P(biphenyl-2-yl)(t-Bu)2; Pd(OAc)2 / o-xylene / 48 h / Heating View Scheme

lithium diisopropyl amide in tetrahydrofuran T=-80°C; Inert atmosphere;

1: With lithium diisopropyl amide in tetrahydrofuran T=-80°C; 2: With 1,2-dibromo-1,1,2,2-tetrachloroethane in tetrahydrofuran T=-80 - 0°C; 1 h;