(S)-5-Hydroxynorvaline 4 has been prepared from L-glutamic acid 1 by simult
aneous protection of the cx-amino and a-carboxyl groups, and selective redu
ction of the resulting boroxazolidone 2. This method is rapid and highly re
producible, and gives very pure (S)-5-hydroxynorvaline after simple anion-e
xchange purification. It improves existing methods by providing a purer pro
duct in higher yields. (C) 2000 Elsevier Science Ltd. All rights reserved.