1: 90 percent / imidazole / dimethylformamide / 3 h / 55 °C 2: 1.) (dba)3Pd2*CHCl3, TPP, Et3N, 2.) TBAF / 1.) toluene, reflux, 2 h, 2.) THF, RT, 30 h View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: tetrahydrofuran / 0.75 h / -78 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1: 2.7 g / CF₃COOH, H₂O / tetrahydrofuran / 6.5 h / Ambient temperature<br />2: tetrahydrofuran / 0.75 h / -78 &deg;C<br /> <br /> &nbsp;

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<b>Multi-step reaction with 3 steps<br /> </b>1: CF₃COOH, H₂O / tetrahydrofuran / 1.5 h / Ambient temperature<br />2: tetrahydrofuran / 0.75 h / -78 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 5 steps<br /> </b>1: 2.) imidazole / 1.) THF, from 0 deg C do RT, 2.) DMF, 55 deg C<br />2: CF₃CO₂H, H₂O / tetrahydrofuran / Ambient temperature<br />3: tetrahydrofuran / -78 &deg;C<br />4: 1.) PhCO₂H, Ph₃P, DEADCAT, 2.) diisobutylaluminum hydride (DIBAL-H) / 1.) THF, RT, 2.) CH₂Cl₂, -78 deg C<br />5: 92 percent<br /> <br /> &nbsp;