1: N-bromosuccinmide / tetrachloromethane / 0.25 h / Reflux 2: toluene-4-sulfonic acid / toluene / 1 h / Reflux View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: caesium carbonate / tetrahydrofuran / 0.5 h / 0 &deg;C / Inert atmosphere<br />2: Oxonereg;; C₈H₆O₄^(2-)*Cu⁽²⁺⁾ / toluene / 6 h / 60 &deg;C / Molecular sieve; Air atmosphere<br /> <br /> &nbsp;

<b>Multi-step reaction with 7 steps<br /> </b>1: pyridine / 6 h / 20 &deg;C<br />2: hydrogen bromide; acetic acid / dichloromethane / 3 h / 0 &deg;C<br />3: CuSO_4‵5H₂O; acetic acid; zinc / water / 2.5 h / 0 &deg;C<br />4: methanol; sodium methylate / 4 h / 20 &deg;C<br />5: dipyridinium dichromate; acetic acid / ethyl acetate / 16 h / 20 &deg;C<br />6: caesium carbonate / tetrahydrofuran / 0.5 h / 0 &deg;C / Inert atmosphere<br />7: Oxonereg;; C₈H₆O₄^(2-)*Cu⁽²⁺⁾ / toluene / 6 h / 60 &deg;C / Molecular sieve; Air atmosphere<br /> <br /> &nbsp;

<b>Multi-step reaction with 6 steps<br /> </b>1: hydrogen bromide; acetic acid / dichloromethane / 3 h / 0 &deg;C<br />2: CuSO_4‵5H₂O; acetic acid; zinc / water / 2.5 h / 0 &deg;C<br />3: methanol; sodium methylate / 4 h / 20 &deg;C<br />4: dipyridinium dichromate; acetic acid / ethyl acetate / 16 h / 20 &deg;C<br />5: caesium carbonate / tetrahydrofuran / 0.5 h / 0 &deg;C / Inert atmosphere<br />6: Oxonereg;; C₈H₆O₄^(2-)*Cu⁽²⁺⁾ / toluene / 6 h / 60 &deg;C / Molecular sieve; Air atmosphere<br /> <br /> &nbsp;