Diastereoselective Photooxidation and Reduction of Chiral Iridium(III) Complexes
A diastereoselective photooxidation of α-amino acid (AA) complexes into imino acid complexes using a chiral iridium(III) complex as a photosensitizer and stereo-controller under visible light irradiation and oxygen was developed. It was found that the oxidative rate of Δ-[Ir(pq)2(L-AA)] (pq is 2-p...
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Veröffentlicht in: | Inorganic chemistry 2019-01, Vol.58 (1), p.785-793 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | A diastereoselective photooxidation of α-amino acid (AA) complexes into imino acid complexes using a chiral iridium(III) complex as a photosensitizer and stereo-controller under visible light irradiation and oxygen was developed. It was found that the oxidative rate of Δ-[Ir(pq)2(L-AA)] (pq is 2-phenylquinoline) diastereomer is significantly higher than that of the corresponding Δ-[Ir(pq)2(D-AA)] diastereomer, providing a new protocol for kinetic resolution of AAs via a nonenzymatic pathway. Moreover, the thermodynamic controlled strategy offered a complemental method for the diastereoselective hydrogenation of imine bonds using NaBH4 as a reductant under the chiral Ir(III) complex as a stereo-controller. The combination of diastereoselective photooxidation and reduction processes results in a new protocol for deracemization of α-amino acids under mild conditions. Mechanism study strongly indicates that singlet oxygen is a key participant in the reaction and the α-C–H bond cleavage of AAs is the rate-determining step. |
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ISSN: | 0020-1669 1520-510X |
DOI: | 10.1021/acs.inorgchem.8b02934 |