[1,2]‐Shift in Chiral Ni(II) Schiff‐Base Derivatives: Conversion of α‐ Thiobenzylated Amino Acid into the Cysteine Derivative

Abstract

The first example of the anionic [1,2]-shift taking place in the metal coordination environment is described. The α-thiobenzylated glycine in the form of the Ni(II) Schiff-base complex is converted into the corresponding cysteine derivative with ca 70 % yield. The reaction disclosed emphasizes how the reactivity of a substrate can be influenced by noncovalent interactions in the metal coordination environment.

Sequential Heck Cross-Coupling and Hydrothiolation Reactions Taking Place in the Ligand Sphere of a Chiral Dehydroalanine Ni(II) Complex: Asymmetric Route to β-Aryl Substituted Cysteines

“…Having a considerable interest in cysteine derivatives, chemists put efforts into elaborating synthetic protocols for this class of AA, especially in an enantioselective manner. To date, there are several methods for the synthesis of β-disubstituted cysteine derivatives in literature. ,, For example, Nagasawa and Hruby groups independently reported the synthesis of racemic β-mono- and β,β-disubstituted cysteines via the Michael addition of sulfur anions to dehydroalanine derivatives. , Marquet et al developed the asymmetric synthesis of 3-mercaptophenylalanine via ring opening of the aziridines with thiols . Michel and colleagues synthesized the racemic erythro and threo S- p -methylbenzyl-β-phenyl cysteine by addition of p -methylbenzyl thiol to 4-benzylidene-2-methyloxazol-5-one .…”