S. Cumberbatch et al., THE SYNTHESIS AND CONFORMATIONAL-ANALYSIS OF A PAIR OF DIASTEREOMERIC, CONFORMATIONALLY CONSTRAINED PEPTIDES WITH OPPOSITE AMIDE BOND GEOMETRIES, Tetrahedron, 49(40), 1993, pp. 9049-9066
Eight membered ring containing, conformationally constrained peptides
derived from cyclo-[(R)-cysteinyl-(R)-penicillamine] contain a cis ami
de bond, whilst the diastereomeric peptides derived from cyclo-[(R)-cy
steinyl-(S)-penicillamine] contain a trans amide bond.