1: (3S,4S)-4-[(tert-butoxycarbonyl)amino]-3-hydroxy-6-methylheptanonitrile With hydrogenchloride in tetrahydrofuran T=120°C; 12 h; 2: di-tert-butyl dicarbonate With sodium hydrogencarbonate in methanol T=20°C; 2 h;

1: 85 percent / p-TsOH*H2O / benzene / 1 h / Heating 2: 86 percent / DIBAH / diethyl ether; toluene / 0.25 h / -40 °C 3: 85 percent / 2-methyl-2-propanol; 5 percent NaH2PO4; 1M KMnO4 4: 80 percent / 85 percent AcOH / 0.67 h / 70 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1.1: trimethyloxonium tetrafluoroborate / petroleum ether / 1 h / 20 &deg;C<br />1.2: 63 percent / K₂CO₃ / CH₂Cl₂; H₂O / 24 h<br />2.1: toluene / 1 h / -15 &deg;C<br />2.2: 59 percent / conc. HCl / toluene; methanol / 1 h / -15 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 4 steps<br /> </b>1.1: ZnBr₂ / tetrahydrofuran / 1.5 h / 0 &deg;C<br />1.2: 75 percent / DIBALH / tetrahydrofuran; toluene / 1 h / -78 &deg;C<br />2.1: 90 percent / TiCl₃; aq. HCl / ethanol / 0.33 h / 20 &deg;C<br />3.1: trimethyloxonium tetrafluoroborate / petroleum ether / 1 h / 20 &deg;C<br />3.2: 63 percent / K₂CO₃ / CH₂Cl₂; H₂O / 24 h<br />4.1: toluene / 1 h / -15 &deg;C<br />4.2: 59 percent / conc. HCl / toluene; methanol / 1 h / -15 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1.1: 90 percent / TiCl₃; aq. HCl / ethanol / 0.33 h / 20 &deg;C<br />2.1: trimethyloxonium tetrafluoroborate / petroleum ether / 1 h / 20 &deg;C<br />2.2: 63 percent / K₂CO₃ / CH₂Cl₂; H₂O / 24 h<br />3.1: toluene / 1 h / -15 &deg;C<br />3.2: 59 percent / conc. HCl / toluene; methanol / 1 h / -15 &deg;C<br /> <br /> &nbsp;

<b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '3570522', constants.ctx, '0')">tetrabutyl ammonium fluoride</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '102391', constants.ctx, '0')">tetrahydrofuran</a> <br />T=60&deg;C;&nbsp;12&nbsp;h;&nbsp;<br /> &nbsp;

Stage #1: &nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '635760', constants.ctx, '0')">toluene</a> <br />T=-15&deg;C;&nbsp;1&nbsp;h;&nbsp;<br />Stage #2: <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1098214', constants.ctx, '0')">hydrogenchloride</a>&nbsp;<b>in</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '1098229', constants.ctx, '0')">methanol</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '635760', constants.ctx, '0')">toluene</a> <br />T=-15&deg;C;&nbsp;1&nbsp;h;&nbsp;<br /> &nbsp;