boron trifluoride diethyl etherate in dichloromethane T=25°C; 24 h;

<b>Multi-step reaction with 2 steps<br /> </b>1: 64 percent / ethyl carbonate, KOH / ethanol / 0.25 h / Heating<br />2: 70 percent / pyridine / CH₂Cl₂ <br /> <br /> &nbsp;