1: H2O / PPTS / tetrahydrofuran / 1.5 h / Heating 2: PCC, sodium acetate / CH2Cl2 / 2.5 h 3: 1.) LDA, 1,10-phenanthroline / 1.) THF, -78 deg C, 15 min; 2.) THF, -20 deg C, 5 min. 4: 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulphonate / copper(II) iodide / acetonitrile / 4 h / 55 - 58 °C 5: 90 percent / KOH / aq. ethanol / 3 h / Heating View Scheme

1: H2O / PPTS / tetrahydrofuran / 1.5 h / Heating 2: PCC, sodium acetate / CH2Cl2 / 2.5 h 3: 1.) LDA, 1,10-phenanthroline / 1.) THF, -78 deg C, 15 min; 2.) THF, -20 deg C, 5 min. 4: 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulphonate / copper(II) iodide / acetonitrile / 4 h / 55 - 58 °C 5: 90 percent / KOH / aq. ethanol / 3 h / Heating View Scheme