Chiral cis-iron(ii ) complexes with metal- and ligand-centered chirality for highly regio- and enantioselective alkylation of N-heteroaromatics
| Autor: | Chi-Ming Che, Cong-Ying Zhou, Bei Cao, Xiaoyong Chang, Chun-Wai Tse, Jinhu Wei |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Chemical Science |
| ISSN: | 2041-6539 2041-6520 |
| DOI: | 10.1039/c9sc04858h |
| Popis: | Iron-catalyzed highly regio- and enantioselective organic transformations with generality and broad substrate scope have profound applications in modern synthetic chemistry; an example is herein described based on cis-FeII complexes having metal- and ligand-centered chirality. The cis-β FeII(N4) complex [FeII(L)(OTf)2] (L = N,N′-bis(2,3-dihydro-1H-cyclopenta-[b]quinoline-5-yl)-N,N′-dimethylcyclohexane-1,2-diamine) is an effective chiral catalyst for highly regio- and enantioselective alkylation of N-heteroaromatics with α,β-unsaturated 2-acyl imidazoles, including asymmetric N1, C2, C3 alkylations of a broad range of indoles (34 examples) and alkylation of pyrroles and anilines (14 examples), all with high product yields (up to 98%), high enantioselectivity (up to >99% ee) and high regioselectivity. DFT calculations revealed that the “chiral-at-metal” cis-β configuration of the iron complex and a secondary π–π interaction are responsible for the high enantioselectivity. A cis-β FeII complex having metal- and ligand-centered chirality catalyzes highly regio- and enantioselective alkylation of indoles (at the N1, C2, or C3 position), pyrroles and anilines with α,β-unsaturated 2-acyl imidazoles (48 examples, up to 99% ee). |
| Databáze: | OpenAIRE |
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