Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D-3-Symmetric Trefoil Knot

Gil-Ramirez, Guzman; Hoekman, Steven; Kitching, Matthew O.; Leigh, David A.; Vitorica-Yrezabal, Inigo J.; Zhang, Gen

Abstract

We report the stereoselective synthesis of a left-handed trefoil knot from a tris(2,6-pyridinedicarboxamide) oligomer with six chiral centers using a lanthanide(III) ion template. The oligomer folds around the lanthanide ion to form an overhand knot complex of single handedness. Subsequent joining of the overhand knot end groups by ring-closing olefin metathesis affords a single enantiomer of the trefoil knot in 90% yield. The knot topology and handedness were confirmed by NMR spectroscopy, mass spectrometry, and X-ray crystallography. The pseudo-D3-symmetric knot was employed as an asymmetric catalyst in Mukaiyama aldol reactions, generating enantioselectivities of up to 83:17 er, which are significantly higher than those obtained with a comparable unknotted ligand complex.

Citation

Gil-Ramirez, G., Hoekman, S., Kitching, M. O., Leigh, D. A., Vitorica-Yrezabal, I. J., & Zhang, G. (2016). Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D-3-Symmetric Trefoil Knot. Journal of the American Chemical Society, 138(40), 13159-13162. https://doi.org/10.1021/jacs.6b08421

• Journal Article Type: Article
• Acceptance Date: Aug 11, 2016
• Online Publication Date: Sep 29, 2016
• Publication Date: Sep 26, 2016
• Deposit Date: Aug 8, 2018
• Publicly Available Date: Aug 16, 2018
• Journal: Journal of the American Chemical Society
• Print ISSN: 0002-7863
• Electronic ISSN: 1520-5126
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 138
• Issue: 40
• Pages: 13159-13162
• DOI: https://doi.org/10.1021/jacs.6b08421
• Public URL: https://durham-repository.worktribe.com/output/1323953