Exploitation of Dimeric Cyclic Cysteine as Helix Inducer in Ultra‐Short Peptides for Cu(II)‐Catalyzed Asymmetric Michael Addition on Chalcones

A dimeric cyclic cysteine analogue, i. e. (1R,1'R,2R,2'R)-2,2'-disulfanediylbis (aminocyclohexane-1-carboxylic acid), was used as a constrained unnatural amino acid and folding inducer in ultra-short Leu-Val-containing peptide. Our results showed that both free dimer L1 its peptide derivative L2 are able to chelate Cu(II). The obtained complexes resulted be catalytically active Michael addition reaction of nitromethane on different types chalcones. L1-Cu(II) shown more reactive terms conversion, while, neat conditions, L2-Cu(II) allows obtain an interesting 60% e.e. pyridine chalcone.