1.1: n-butyllithium / tetrahydrofuran; hexane / -78 - 20 °C / Inert atmosphere 1.2: 16 h / Inert atmosphere; Reflux 2.1: iron; acetic acid / ethanol / 16 h / 80 °C / Inert atmosphere 3.1: trifluoromethanesulfonyl azide; copper(II) sulfate; triethylamine / methanol; dichloromethane; water / 16 h / 20 °C / Inert atmosphere 4.1: dirhodium(II) tetrakis(perfluorobutyrate) / toluene / 16 h / 80 °C / Inert atmosphere; Molecular sieve View Scheme