1: tetrahydrofuran; diethyl ether / 1 h / Heating 2: 1.) ozone, 2.) AcOH, aq. H2SO4, 30percent aq. H2O2 / 1.) CH2Cl2, ethyl acetate, -60 deg C to -30 deg C, 1 h, 2.) ethyl acetate, reflux, 2 h View Scheme

sulfuric acid; dihydrogen peroxide; ozone; acetic acid 1.) CH2Cl2, ethyl acetate, -60 deg C to -30 deg C, 1 h, 2.) ethyl acetate, reflux, 2 h; Multistep reaction;