Ruthenium(II) in ring closing metathesis for the stereoselective preparation of cyclic 1-amino-1-carboxylic acids

Article abstract of DOI:10.1016/S0040-4020(96)01132-5

Stereoselective synthesis of α-amino acids where the α-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)-2,5-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 acid hydrolysis.