Individual (^f,tA)‐ and (^f,tC)‐Fullerene‐Based Nickel(II) Glycinates: Protected Chiral Amino Acids Directly Linked to a Chiral π‐Electron System

Abstract

Stereoselective electrosynthesis of the first individual ( A)- and ( C)-1,4-fullerene derivatives with a non-inherently chiral functionalization pattern is described, as well as the first example of an optically pure protected primary amino acid directly linked to the fullerene through only the chiral α-amino-acid carbon atom. An application of an auxiliary chiral nickel-Schiff base moiety as derivatizing agent allowed separation of ( A)- and ( C)-1,4-fullerene derivatives using an achiral stationary phase, a separation which has never been done before.

Which Stereoinductor Is Better for Asymmetric Functionalization of α‐Amino Acids in a Nickel(II) Coordination Environment? Experimental and DFT Considerations

“…Various types of reactions are compatible with this methodological platform, as represented by alkyl halide alkylations; Michael, Mannich, and aldol addition reactions; as well as multistep transformations, affording a wide range of practically important α‐ and β‐amino acids . Recently, asymmetric synthesis via metal Schiff base complexes was combined with the electrochemical activation approach, which disclosed a virtually unexplored methodological facet of this area of research.…”

Stereoselective Electrosynthesis of β‐Hydroxy‐α‐Amino Acids in the Form of NiII‐Schiff‐Base Complexes

“…Elaboration of new stereoselective synthetic approaches to organic molecules is a topical problem nowadays since the configuration of stereocenters often determines properties of diastereomers and possibilities for their practical applications . Recently, we started an extensive research on the application of electrochemical activation in stereoselective synthesis in a coordination environment of chiral metal complexes . Wide capabilities provided by electrochemical techniques open new horizons in stereoselective synthesis.…”

“…New compounds which were not available using common approaches were obtained when cathodic or anodic activation of the starting compounds was applied . The other possible approach – deprotonation with electrochemically generated base – provides the possibility of a precise control on the concentration of a base and its in situ reaction with the complex, thus opening up the possibility of carrying out multistep stereoselective one‐pot transformations . Here we report a new electrochemical route for the stereoselective oxyalkylation of glycine in a Ni II coordination environment (Scheme ) using in situ electrogenerated active species.…”

Asymmetric Synthesis of Tailor-Made Amino Acids Using Chiral Ni(II) Complexes of Schiff Bases. An Update of the Recent Literature

“…Electrochemical deprotonation of (S)-2 was performed with azobenzene radical-anions (at the potential of their formation, −1.32 V vs. Ag/AgCl/KCl). After complete deprotonation of (S)-2, C60 was added to Magdesieva and co-authors [75] reported the first example of regio-and stereoselective electrosynthesis of the protected primary fulleroamino acid with double chirality (Scheme 28). Compounds (77a and 77b) have three chiral centers in the addend (including the stereogenic α-amino-acid carbon center directly bound to the fullerene) and the fullerene cage itself exhibits a non-inherently chiral 1,4-functionalization pattern.…”

“…Magdesieva and co-authors [ 75 ] reported the first example of regio- and stereoselective electrosynthesis of the protected primary fulleroamino acid with double chirality ( Scheme 28 ). Compounds ( 77a and 77b ) have three chiral centers in the addend (including the stereogenic α-amino-acid carbon center directly bound to the fullerene) and the fullerene cage itself exhibits a non-inherently chiral 1,4-functionalization pattern.…”