sodium hydroxide in methanol Yield given;

<b>Multi-step reaction with 2 steps<br /> </b>1: 83 percent / tetrahydrofuran / 0.25 h / -78 &deg;C<br />2: 1.) Et₂O, THF, 20 deg C, 1 h, 2.) 0 deg C, 4 h<br /> <br /> &nbsp;