摘要:
A robust and practical synthesis of each enantiomer of 2-methyl-azetidine-2-carboxylic acid, based on the use of (S)-phenylglycinol as resolving agent, is described. This synthesis affords practical quantities of this quaternary amino acid suitably N- and C-protected for use in further peptide coupling. Synthetic highlights include the formation of the azetidine ring by intramolecular alkylation and the facile separation of the diastereoisomeric amides derived from phenylglycinol. (C) 2012 Elsevier Ltd. All rights reserved.