1.1: 4-(dimethylamino)pyridine / acetonitrile 2.1: lithium triethylborohydride / tetrahydrofuran / 0.67 h / -78 °C 2.2: H2O2 / tetrahydrofuran / 0.33 h / 0 °C 2.3: 89 percent / triethylsilane; BF3*OEt2 / CH2Cl2 / 3 h / -78 °C 3.1: 86 percent / NaOH / methanol; H2O / 6 h / 20 °C View Scheme

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1921286', constants.ctx, '0')">phosphoric acid</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '102391', constants.ctx, '0')">tetrahydrofuran</a> <br />T=20&deg;C;&nbsp;<br /> <br /> &nbsp;