in xylene; benzene 4 h; Heating;

1: 58 percent / lead teraacetate / acetic acid / 0.5 h 2: 79 percent / benzene; xylene / 4 h / Heating View Scheme

1: 91 percent / sodium acatate / acetic acid / 30 h / Heating 2: 98 percent / H2SO4 / 1.) 1 h.; 2.) rt. 3d.; 3.) AcOH, reflux, 2h. 3: 83 percent / HCl / ethanol; tetrahydrofuran; acetic acid / 1.) EtOH, THF, 0 deg C, 20 min.; 2.) AcOH, 0 deg C., 30 min; 3.) rt. overnight 4: 94 percent / HCl / acetic acid / 9 h / Heating 5: tetrahydrofuran; hexamethylphosphoric acid triamide / 18 h / Ambient temperature 6: 56 percent / trimethylsilyl triflate / tetrahydrofuran; hexamethylphosphoric acid triamide; diethyl ether / 1.) -20 deg C, 15 min.; 2.) -40 deg C, 2 h.; 3.) -40 deg C, 1 h. View Scheme

1: 91 percent / sodium acatate / acetic acid / 30 h / Heating 2: 98 percent / H2SO4 / 1.) 1 h.; 2.) rt. 3d.; 3.) AcOH, reflux, 2h. View Scheme