1: With hydrogenchloride; water in isopropyl alcohol T=45°C; 6.5 h; 2: With sodium hydroxide in water

1.1: hydrogenchloride / 1,4-dioxane; dichloromethane / 3 h / 20 °C 2.1: triethylamine / tetrahydrofuran / 20 h / 65 °C 3.1: lithium hexamethyldisilazane / tetrahydrofuran / 1 h / -78 °C 3.2: 0.5 h / -78 °C 3.3: 2 h / -78 - 0 °C 4.1: trifluoroacetic acid / dichloromethane / 16 h / 20 °C 5.1: benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine / dichloromethane / 20 °C 6.1: N,N-diethylaniline / ethanol; hexane / Resolution of racemate View Scheme

Stage #1: <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '103296', constants.ctx, '0')">2,2,6,6-tetramethyl-piperidine</a>;&nbsp;<a href="#" onclick="return RXDsubstances(event, this, '1209227', constants.ctx, '0')">n-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, '1730733', constants.ctx, '0')">hexane</a> <br />T=-78 - -70&deg;C;&nbsp;&nbsp;Inert atmosphere;&nbsp;<br />Stage #2: <b>With</b>&nbsp; <a href="#" onclick="return RXDsubstances(event, this, '5348902', constants.ctx, '0')">N-fluoro-N-(phenylsulfonyl)benzene-sulfonamide</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=-20&deg;C;&nbsp;&nbsp;Inert atmosphere;&nbsp;<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1.1: sodium hydroxide; water / dichloromethane / Cooling with ice<br />2.1: 2-methyl tetrahydrofuran / 22 &deg;C<br />3.1: 2,2,6,6-tetramethyl-piperidine; n-butyllithium / hexane; tetrahydrofuran / -78 - -70 &deg;C / Inert atmosphere<br />3.2: -20 &deg;C / Inert atmosphere<br /> <br /> &nbsp;

<b>Multi-step reaction with 4 steps<br /> </b>1.1: dichloromethane / 20 &deg;C<br />1.2: 20.08 h / 14 - 30 &deg;C<br />2.1: sodium hydroxide; water / dichloromethane / Cooling with ice<br />3.1: 2-methyl tetrahydrofuran / 22 &deg;C<br />4.1: 2,2,6,6-tetramethyl-piperidine; n-butyllithium / hexane; tetrahydrofuran / -78 - -70 &deg;C / Inert atmosphere<br />4.2: -20 &deg;C / Inert atmosphere<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1.1: 2-methyl tetrahydrofuran / 22 &deg;C<br />2.1: 2,2,6,6-tetramethyl-piperidine; n-butyllithium / hexane; tetrahydrofuran / -78 - -70 &deg;C / Inert atmosphere<br />2.2: -20 &deg;C / Inert atmosphere<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1.1: 2-methyl tetrahydrofuran / 22 &deg;C<br />2.1: 2,2,6,6-tetramethyl-piperidine; n-butyllithium / hexane; tetrahydrofuran / -78 - -70 &deg;C / Inert atmosphere<br />2.2: -20 &deg;C / Inert atmosphere<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1.1: triethylamine / dichloromethane / 5 h / 20 &deg;C<br />2.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 &deg;C / Inert atmosphere<br />2.2: -78 - 20 &deg;C / Inert atmosphere<br /> <br /> &nbsp;