Triphenylphosphine → (S)-4-(4-Benzyl-2H-tetrazol-5-yl)-2-tert-butoxycarbonylamino-butyric acid benzyl ester

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Reaction Steps

To a suspension of 5.92 g (S)-4-benzylcarbamoyl-2-tert-butoxycarbonylamino-butyric acid benzyl ester and 9.10 g triphenylphosphine in 120 ml acetonitrile were added dropwise at 0° C. 7.1 ml diisopropylazodicarboxylate and after 2 minutes 4.8 ml trimethylsilylazide over a period of 20 minutes. After 30 minutes the mixture was allowed to warm to RT and stirred for 12 h. The mixture was cooled to 0° C. and 4.8 ml aqueous sodium nitrite (2.9 M) were added, after 30 minutes a solution of 7.6 g ceric ammonium nitrate in 15 ml water was added and stirred for another 20 minutes. After this time the mixture was poured into ice and extracted twice with dichloromethane.

Provenance & Evidence