1.1: benzotriazol-1-yloxyl-tris-(pyrrolidino)-phosphonium hexafluorophosphate; N-ethyl-N,N-diisopropylamine / dichloromethane / 0.17 h / 0 °C 1.2: 0 - 20 °C 2.1: trifluoroacetic acid / dichloromethane / 0 - 20 °C 3.1: benzotriazol-1-ol; N-ethyl-N,N-diisopropylamine; HATU / dichloromethane; acetonitrile 4.1: triethylsilane; trifluoroacetic anhydride / 2 h / 0 - 20 °C 5.1: triethylamine / dichloromethane / 3 h / 0 - 20 °C View Scheme