1: DMSO, oxalyl chloride / tetrahydrofuran / 0.33 h / -70 °C 2: 1.) t-BuLi / 1.) hexane, THF, 0 deg C, 1 h, 2.) THF, hexane, RT, 20 h View Scheme

Stage #1: <a href="#" onclick="return RXDsubstances(event, this, '106436', constants.ctx, '0')">tetrahydropyran-2-one</a> <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '4123663', constants.ctx, '0')">diisobutylaluminium hydride</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '102391', constants.ctx, '0')">tetrahydrofuran</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '1730733', constants.ctx, '0')">hexane</a> <br />T=-40 - -5&deg;C;&nbsp;1&nbsp;h;&nbsp;<br />Stage #2: <a href="#" onclick="return RXDsubstances(event, this, '2055793', constants.ctx, '0')">Ph₃P=CH(OMe)</a> <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '3587206', constants.ctx, '0')">sec.-butyllithium</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '102391', constants.ctx, '0')">tetrahydrofuran</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '1900225', constants.ctx, '0')">cyclohexane</a> <br />T=20&deg;C;&nbsp;16&nbsp;h;&nbsp;&nbsp;Further stages.;&nbsp;<br /> &nbsp;

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1209227', constants.ctx, '0')">n-butyllithium</a> <br />&nbsp;1.) hexane, THF, 0 deg C, 30 min, 2.) THF, RT, 20 h;&nbsp;&nbsp;Yield given. Multistep reaction;&nbsp;<br /> &nbsp;

&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1696894', constants.ctx, '0')">diethyl ether</a> <br />Wittig reaction;&nbsp;<br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1: 93 percent / DIBAL-H / diethyl ether; hexane / 2 h / -78 &deg;C<br />2: 50 percent / diethyl ether<br /> <br /> &nbsp;