1: sodium periodate; silica gel / tetrahydrofuran; diethyl ether; water / 0.5 h / 20 °C 2: triethylamine / N,N-dimethyl-formamide / 48 h / 20 °C / Inert atmosphere 3: tris-[2-carboxyethyl]-phosphine / water; acetonitrile / pH 7.4 / aq. phosphate buffer; Inert atmosphere 4: water; acetonitrile / pH 7.4 / aq. phosphate buffer; Inert atmosphere View Scheme

1.1: sodium periodate; silica gel / tetrahydrofuran; diethyl ether; water / 0.5 h / 20 °C 2.1: triethylamine / N,N-dimethyl-formamide / 48 h / 20 °C / Inert atmosphere 3.1: tris-[2-carboxyethyl]-phosphine / water; acetonitrile / pH 7.4 / aq. phosphate buffer; Inert atmosphere 4.1: water; acetonitrile / pH 7.4 / aq. phosphate buffer; Inert atmosphere 5.1: sulfuric acid; sodium nitrite / tetrahydrofuran; water / 1 h / 0 °C 5.2: 0 - 20 °C 6.1: dipyridinium dichromate / dichloromethane / 4 h / 20 °C View Scheme