1: oxalic acid / H2O / 0.67 h / Heating 2: 92 percent / PCl5 / CCl4 View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: n-butyllithium / tetrahydrofuran; hexane<br />2: sodium borohydride, 40percent aq. KOH / tetrahydrofuran; aq. ethanol / -30 &deg;C<br /> <br /> &nbsp;