in propionic acid 16 h; Heating;

Multi-step reaction with 4 steps 1: 68 percent / n-butyllithium / diethyl ether / 1.) rt, 1 h, 2.) 0 - 4 deg C, 4 h2: 79 percent / n-BuLi / diethyl ether / 1.) r.t, 1 h, 2.) 0 - 5 deg C, 3 h3: 90 percent / p-TsOH / ethanol / 4 h / Heating4: 87 percent / MnO2 / acetone / 1 h / Ambient temperature