Elevated Catalytic Activity of Ruthenium(II)–Porphyrin‐Catalyzed Carbene/Nitrene Transfer and Insertion Reactions with N‐Heterocyclic Carbene Ligands1. (12th February 2014)

• Record Type: Journal Article
• Authors: Chan, Ka‐Ho; Guan, Xiangguo; Lo, Vanessa Kar‐Yan; Che, Chi‐Ming
• Is Part Of: Angewandte Chemie. Volume 126:Number 11(2014)
• Page Start: 3026
• Page End: 3031
• Publication Date: 2014-02-12
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201309888
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Bis(NHC)ruthenium(II)–porphyrin complexes were designed, synthesized, and characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the <italic>trans</italic> MCRR′/MNR moiety, these complexes showed unprecedently high catalytic activity towards alkene cyclopropanation, carbene CH, NH, SH, and OH insertion, alkene aziridination, and nitrene CH insertion with turnover frequencies up to 1950 min⁻¹. The use of chiral [Ru(<italic>D</italic>₄‐Por)(BIMe)₂] (<bold>1 g</bold>) as a catalyst led to highly enantioselective carbene/nitrene transfer and insertion reactions with up to 98 % <italic>ee</italic>. Carbene modification of the N terminus of peptides at 37 °C was possible. DFT calculations revealed that the <italic>trans</italic> axial NHC ligand facilitates the decomposition of diazo compounds by stabilizing the metal–carbene reaction intermediate.</p> </abstract>