1.1: 99 percent / K2CO3 / methanol / 3 h 2.1: 85 percent / oxalyl chloride; DMSO; Et3N / CH2Cl2 / -78 - 20 °C 3.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 57 percent / HMPA / tetrahydrofuran; hexane / 22 h / -20 - -10 °C 4.1: 100 percent / tetrabutylammonium fluoride / tetrahydrofuran / 1 h / 0 °C 5.1: 87 percent / iPr2NEt; SO3*pyridine / CH2Cl2; dimethylsulfoxide / 2 h / 20 °C View Scheme

1: 99 percent / K2CO3 / methanol / 3 h 2: 85 percent / oxalyl chloride; DMSO; Et3N / CH2Cl2 / -78 - 20 °C View Scheme

potassium carbonate in methanol 3 h;

1.1: 99 percent / K2CO3 / methanol / 3 h 2.1: 85 percent / oxalyl chloride; DMSO; Et3N / CH2Cl2 / -78 - 20 °C 3.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 57 percent / HMPA / tetrahydrofuran; hexane / 22 h / -20 - -10 °C 4.1: 100 percent / tetrabutylammonium fluoride / tetrahydrofuran / 1 h / 0 °C 5.1: 87 percent / iPr2NEt; SO3*pyridine / CH2Cl2; dimethylsulfoxide / 2 h / 20 °C 6.1: 72 percent / LiBr; PPh3; diisopropyl azodicarboxylate / tetrahydrofuran / 3 h View Scheme

<b>Multi-step reaction with 3 steps<br /> </b>1.1: 100 percent / tetrabutylammonium fluoride / tetrahydrofuran / 1 h / cooling<br />2.1: 95 percent / DMAP; pyridine / CH₂Cl₂ / 1 h<br />3.1: tert-butyllithium / tetrahydrofuran; pentane / 0.5 h / -78 &deg;C<br />3.2: ZnCl₂ / tetrahydrofuran; pentane / -78 - 20 &deg;C<br />3.3: 91 percent / Pd(PPh₃)4 / tetrahydrofuran; pentane / -20 - 5 &deg;C<br /> <br /> &nbsp;