1.1: formic acid / diethyl ether / 10 h / 5 - 20 °C 2.1: [bis(acetoxy)iodo]benzene; water / tetrahydrofuran / 0.67 h / 20 °C 3.1: 2,6-dimethylpyridine / dichloromethane / 4 h / 0 - 5 °C 3.2: 3 h / 5 °C 4.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 4 h / 20 °C 5.1: 2,4,6-trichlorobenzoyl chloride; triethylamine / tetrahydrofuran / 1 h / 0 °C 5.2: 10.33 h / 20 °C 6.1: trifluoroacetic acid / dichloromethane / 1 h / -20 - 0 °C View Scheme

1.1: formic acid / diethyl ether / 10 h / 5 - 20 °C 2.1: [bis(acetoxy)iodo]benzene; water / tetrahydrofuran / 0.67 h / 20 °C 3.1: 2,6-dimethylpyridine / dichloromethane / 4 h / 0 - 5 °C 3.2: 3 h / 5 °C View Scheme

<b>Multi-step reaction with 8 steps<br /> </b>1.1: pyridine; 4-(N,N-dimethlyamino)pyridine / 3 h / -20 - 5 &deg;C<br />1.2: 5 &deg;C<br />2.1: magnesium; ethylene dibromide; N-ethyl-N,N-diisopropylamine / diethyl ether; toluene / 2 h / 100 &deg;C<br />3.1: n-butyllithium / diethyl ether; hexane / 3 h / -78 &deg;C<br />3.2: 20 &deg;C<br />3.3: 0.08 h / 0 &deg;C<br />4.1: potassium <i>tert</i>-butylate / <i>tert</i>-butyl alcohol / 1 h / Reflux<br />4.2: 1 h / Reflux<br />5.1: 1H-imidazole / N,N-dimethyl-formamide / 12 h / 0 - 5 &deg;C<br />6.1: dimethylsulfide borane complex; (+)-(1R,5R)-α-pinene / tetrahydrofuran / 0 - 20 &deg;C<br />6.2: 2 h / 20 &deg;C<br />7.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / -78 &deg;C<br />7.2: -78 - 0 &deg;C<br />8.1: n-butyllithium; diisopropylamine / tetrahydrofuran / 1.75 h / -78 - 40 &deg;C<br />8.2: 0.08 h / -78 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 7 steps<br /> </b>1.1: magnesium; ethylene dibromide; N-ethyl-N,N-diisopropylamine / diethyl ether; toluene / 2 h / 100 &deg;C<br />2.1: n-butyllithium / diethyl ether; hexane / 3 h / -78 &deg;C<br />2.2: 20 &deg;C<br />2.3: 0.08 h / 0 &deg;C<br />3.1: potassium <i>tert</i>-butylate / <i>tert</i>-butyl alcohol / 1 h / Reflux<br />3.2: 1 h / Reflux<br />4.1: 1H-imidazole / N,N-dimethyl-formamide / 12 h / 0 - 5 &deg;C<br />5.1: dimethylsulfide borane complex; (+)-(1R,5R)-α-pinene / tetrahydrofuran / 0 - 20 &deg;C<br />5.2: 2 h / 20 &deg;C<br />6.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / -78 &deg;C<br />6.2: -78 - 0 &deg;C<br />7.1: n-butyllithium; diisopropylamine / tetrahydrofuran / 1.75 h / -78 - 40 &deg;C<br />7.2: 0.08 h / -78 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 4 steps<br /> </b>1.1: 1H-imidazole / N,N-dimethyl-formamide / 12 h / 0 - 5 &deg;C<br />2.1: dimethylsulfide borane complex; (+)-(1R,5R)-α-pinene / tetrahydrofuran / 0 - 20 &deg;C<br />2.2: 2 h / 20 &deg;C<br />3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / -78 &deg;C<br />3.2: -78 - 0 &deg;C<br />4.1: n-butyllithium; diisopropylamine / tetrahydrofuran / 1.75 h / -78 - 40 &deg;C<br />4.2: 0.08 h / -78 &deg;C<br /> <br /> &nbsp;