1.1: N,N,N',N'-tetramethylethylenediamine; TMSOTf / diethyl ether; pentane / 0.58 h / 0 - 20 °C 1.2: N,N,N',N'-tetramethylethylenediamine; n-BuLi / diethyl ether; pentane / 1 h / -78 °C 1.3: 86 percent / I2 / diethyl ether; pentane / 1 h / -78 °C 2.1: 94 percent / 2 M NaOH / ethanol / 2 h / 20 °C View Scheme

1.1: TMEDA / diethyl ether; pentane / 0.5 h / 20 °C 2.1: TMEDA; n-BuLi / 1 h / -78 °C 2.2: 1 h / -78 °C 2.3: 0.141 g / NaOH / ethanol / 2 h / 20 °C View Scheme