Bis-Cyclometalated Indazole and Benzimidazole Chiral-at-Iridium Complexes: Synthesis and Asymmetric Catalysis
A new class of bis-cyclometalated iridium(III) catalysts containing two inert cyclometalated 6-<i>tert</i>-butyl-2-phenyl-2<i>H</i>-indazole bidentate ligands or two inert cyclometalated 5-<i>tert</i>-butyl-1-methyl-2-phenylbenzimidazoles is introduced. The coordi...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-03-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/26/7/1822 |
| Summary: | A new class of bis-cyclometalated iridium(III) catalysts containing two inert cyclometalated 6-<i>tert</i>-butyl-2-phenyl-2<i>H</i>-indazole bidentate ligands or two inert cyclometalated 5-<i>tert</i>-butyl-1-methyl-2-phenylbenzimidazoles is introduced. The coordination sphere is complemented by two labile acetonitriles, and a hexafluorophosphate ion serves as a counterion for the monocationic complexes. Single enantiomers of the chiral-at-iridium complexes (>99% er) are obtained through a chiral-auxiliary-mediated approach using a monofluorinated salicyloxazoline and are investigated as catalysts in the enantioselective conjugate addition of indole to an α,β-unsaturated 2-acyl imidazole and an asymmetric Nazarov cyclization. |
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| ISSN: | 1420-3049 |