Synthesis of novel boron containing unnatural cyclic amino acids as potential therapeutic agents

Two boronated alpha -amino acids, 1-amino-3-boronocyclopentanecarboxylic ac id and 1-amino-3-boronocycloheptanecarboxylic acid were prepared. The key s tep in the syntheses was the 1,4-boration of the alpha,beta -unsaturated cy clic ketones using the bis-pinacolatodiboron ester to generate the boronate d ketones which were then converted to the corresponding amino acids. (C) 2 001 Elsevier Science Ltd. All rights reserved.