Chiral manganese complexes with pinene appended tetradentate ligands as stereoselective epoxidation catalysts

Text Complet
ChiralManganese.pdf closed access
Sol·licita còpia a l'autor de l'article
En omplir aquest formulari esteu demanant una còpia de l'article dipositat al repositori institucional (DUGiDocs) al seu autor o a l'autor principal de l'article. Serà el mateix autor qui decideixi lliurar una còpia del document a qui ho sol•liciti si ho creu convenient. En tot cas, la Biblioteca de la UdG no intervé en aquest procés ja que no està autoritzada a facilitar articles quan aquests són d'accés restringit.
Compartir
A novel family of chiral manganese complexes Λ-1(CF 3SO3) and Δ-2(CF3SO3), have been stereoselectively prepared, characterized and studied as epoxidation catalysts. The complexes are structurally related to [MnII(CF 3SO3)2(α-MCP)] (MCP = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)cyclohexane-trans-1, 2-diamine), recently reported as a very efficient epoxidation catalyst in combination with peracetic acid. Pinene rings have been fused to the 4 and 5 positions of the two pyridine groups of the ligand, giving rise to complexes where the two labile binding sites of the manganese ion are confined in a better-defined chiral pocket than in the parent [MnII(CF 3SO3)2(α-MCP)]. Chirality in these complexes arises from the stereochemistry of the trans-diaminocyclohexane ring, from the pinene ring and also from the topological chirality adopted by the ligand upon binding to the manganese ion. While previous studies have demonstrated that small modifications in the structure of the MCP ligand result in a dramatic loss of efficiency, Λ-1(CF3SO3) and Δ-2(CF3SO3) exhibit comparable catalytic activity to [MnII(CF3SO3)2(α-MCP)]. In addition, the complexes exhibit a remarkable stereoselectivity (up to 46% ee) in the epoxidation of selected substrates. The results reported in this work point towards modification of the 4 and 5 positions of the pyridine groups as a new strategy towards the design of stereoselective versions of this family of highly active and environmentally benign epoxidation catalysts ​
​Tots els drets reservats