RUTHENIUM(II) IN RING CLOSING METATHESIS FOR THE STEREOSELECTIVE PREPARATION OF CYCLIC 1-AMINO-1-CARBOXYLIC ACIDS

摘要

Stereoselective synthesis of alpha-amino acids where the alpha-carbon of the amino acid is incorporated into a five-, six- or seven-membered ring is described. The stereoselective control results from stepwise bisalkenylation of (R)-25-dihydro-3,6-dimethoxy-2-isopropylpyrazine. Ring closing metathesis was effected by ruthenium(II)-catalysis. The spiro-cycloalkene intermediates were further transformed into 1-aminocycloalkene-1-carboxylic acid derivatives by mild add hydrolysis. (C) 1997, Elsevier Science Ltd. [References: 42]