1.1: pyrrolidine; BuLi / tetrahydrofuran; hexane / 2 h / -30 °C 1.2: tetrahydrofuran / 2.5 h / -30 - -10 °C 1.3: 85 percent / H2O / tetrahydrofuran / 0.33 h / 0 °C 2.1: 92 percent / aq. HCl / tetrahydrofuran / 3 h / 20 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: 91 percent / pyridine / toluene / 18 h / 20 &deg;C<br />2: 51 percent / (EtO)3CH; H₂SO₄ / tetrahydrofuran / 48 h / 20 &deg;C<br /> <br /> &nbsp;

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '2037554', constants.ctx, '0')">sulfuric acid</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '605384', constants.ctx, '0')">orthoformic acid triethyl ester</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;48&nbsp;h;&nbsp;<br /> &nbsp;