1: (i) KOH, triethylene glycol, (heating), (ii) /BRN= 385737/, H2SO4 2: aq. KOH / methanol View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: tetrahydrofuran / 10 h / Reflux<br />2: boron trifluoride diethyl etherate / dichloromethane / 1 h / 20 &deg;C<br /> <br /> &nbsp;

&nbsp;(i) Mg, Et₂O, (ii) /BRN= 2040762/;&nbsp;&nbsp;Multistep reaction;&nbsp;<br /> &nbsp;