AI Article Synopsis
- Researchers developed optically pure transition metal complexes using symmetric N-heterocyclic carbene ligands from prochiral precursors.
- The complexes exhibited stable chirality, achieving high optical purity (up to 99.5% ee) through a specialized purification process.
- The study highlighted a novel mechanism of carbene transfer between metals while maintaining stereochemistry, demonstrating the complexes’ effectiveness in asymmetric catalysis with up to 98% ee.
Article Abstract
Well-defined optically pure transition metal (TM) complexes bearing - and -symmetric N-heterocyclic carbene (NHC) ligands were prepared from prochiral NHC precursors. As predicted by DFT calculations, our strategy capitalizes on the formation of a metal-carbene bond which induces an axis of chirality. Configurationally stable atropisomers of various NHC-containing TM complexes were isolated by preparative HPLC on a chiral stationary phase in good yields and excellent optical purities (up to 99.5% ee). The carbene transfer from an optically pure Cu complex to a gold or palladium center reveals, for the first time, a full stereoretentivity, supporting the hypothesis of an associative mechanism for the transmetalation. The potential of these new chiral TM complexes was illustrated in asymmetric catalysis with up to 98% ee.
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| http://dx.doi.org/10.1021/jacs.9b12698 | DOI Listing |
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