1: 1.) n-BuLi, (2-thienyl)Cu(CN)Li / 1.) THF, -78 deg C; 2.) THF, -78 to 0 deg C, 1 h 2: 76 percent / (2-thienyl)Cu(CN)Li / tetrahydrofuran / -78 deg C up to 0 deg C 3: 87 percent / PPTS / propan-2-ol; diethyl ether / 5 h / Ambient temperature 4: 91 percent / Jones reagent / acetone; diethyl ether / 0.5 h / 0 °C 5: 89 percent / aq. HF / acetonitrile / 0.67 h / Ambient temperature View Scheme

1: 1.) n-BuLi, (2-thienyl)Cu(CN)Li / 1.) THF, -78 deg C; 2.) THF, -78 to 0 deg C, 1 h 2: 80 percent / t-BuLi, (2-thienyl)Cu(CN)Li / tetrahydrofuran; diethyl ether; pentane / 1 h / -78 deg C up to 0 deg C 3: 86 percent / PPTS / propan-2-ol; diethyl ether / 5 h / Ambient temperature 4: 79 percent / Jones reagent / acetone; diethyl ether / 0.5 h / 0 °C 5: 78 percent / aq. HF / acetonitrile / 0.67 h / Ambient temperature View Scheme