Synthesis of bis‐Phenylalanine, A Novel Eight‐Membered Cyclic Dipeptide

Abstract Cyclic eight‐membered ring lactams have been prepared which are formally analogs of Phe‐Ala or Ala‐Phe dipeptides joined together on their side chains. These are termed bis‐phenylalanines because they are phenylalanine with respect to both of the residues in which the phenyl ring is shared between the two. The key synthetic step was the Negishi coupling of Boc‐β‐I‐Ala methyl ester with a suitably protected 2′‐I phenylalanine.