The asymmetric synthesis of. alpha.-amino acids. Electrophilic azidation of chiral imide enolates, a practical approach to the synthesis of (R)-and (S)-. alpha.-azido …

…, TC Britton, JA Ellman, RL Dorow

Index: Evans, David A.; Britton, Thomas C.; Ellman, Jonathan A.; Dorow, Roberta L. Journal of the American Chemical Society, 1990 , vol. 112, # 10 p. 4011 - 4030

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Citation Number: 496

Abstract

Abstract: Two complementary approaches to the asymmetric synthesis of a-amino acids have been achieved. In the initially investigated reaction sequence, the diastereoselective bromination of the illustrated boron enolate with N-bromosuccinimide was followed by stereospecific azide displacement by tetramethylguanidinium azide. The resulting a-azido carboximides may be readily purified to high diastereomeric purity by chromatography on ...