1: toluene-4-sulfonic acid / toluene / 3 h / Dean-Stark conditions; Reflux 2: tetrahydrofuran / 14 h / 18 - 25 °C 3: tributylphosphine / toluene / 8 h / 80 °C View Scheme

toluene-4-sulfonic acid in toluene 3 h; Dean-Stark conditionsReflux;

1: toluene-4-sulfonic acid / toluene / 3 h / Dean-Stark conditions; Reflux 2: tetrahydrofuran / 14 h / 18 - 25 °C View Scheme

1: toluene-4-sulfonic acid / toluene / 3 h / Dean-Stark conditions; Reflux 2: tetrahydrofuran / 18 - 25 °C View Scheme

1: toluene-4-sulfonic acid / toluene / 3 h / Dean-Stark conditions; Reflux 2: tetrahydrofuran / 18 - 25 °C 3: tributylphosphine / toluene / 80 °C / Inert atmosphere View Scheme

Stage #1: <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '11343078', constants.ctx, '0')">sodium tetrahydroborate</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '102391', constants.ctx, '0')">tetrahydrofuran</a> <br />T=0 - 25&deg;C;&nbsp;6&nbsp;h;&nbsp;<br />Stage #2: <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1098214', constants.ctx, '0')">hydrogenchloride</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '3587155', constants.ctx, '0')">water</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '102391', constants.ctx, '0')">tetrahydrofuran</a> <br />T=0&deg;C;&nbsp;pH=4;&nbsp;<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1.1: acetic anhydride / 18 - 25 &deg;C<br />2.1: sodium tetrahydroborate / tetrahydrofuran / 6 h / 0 - 25 &deg;C<br />2.2: 0 &deg;C / pH 4<br /> <br /> &nbsp;