Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D3- Symmetric Trefoil Knot

Guzman Gil-Ramírez; Steven Hoekman; Matthew O.  Kitching; David Leigh; Inigo Vitorica-Yrezabal; Gen Zhang

doi:10.1021/jacs.6b08421

Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D3- Symmetric Trefoil Knot

Guzman Gil-Ramírez, Steven Hoekman, Matthew O. Kitching, David Leigh, Inigo Vitorica-Yrezabal, Gen Zhang

Research output: Contribution to journal › Article › peer-review

Abstract

We report the stereoselective synthesis of a
left-handed trefoil knot from a tri(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
stereoisomer of the trefoil knot in 90% yield. The knot topology
and handedness was 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, significantly higher than those obtained
with a comparable unknotted ligand complex.

Original language	English
Journal	Journal of the American Chemical Society
Volume	138
Issue number	40
Early online date	26 Sept 2016
DOIs	https://doi.org/10.1021/jacs.6b08421
Publication status	Published - 2016

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10.1021/jacs.6b08421Licence: CC BY

CCDC 1494803: Experimental Crystal Structure Determination
Gil-Ramírez, G. (Contributor), Hoekman, S. (Contributor), Kitching, M. O. (Contributor), Leigh, D. (Contributor), Vitorica-Yrezabal, I. (Contributor) & Zhang, G. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2016
DOI: 10.5517/ccdc.csd.cc1m5ggq, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1m5ggq&sid=DataCite
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title = "Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D3- Symmetric Trefoil Knot",

abstract = "We report the stereoselective synthesis of aleft-handed trefoil knot from a tri(2,6-pyridinedicarboxamide) oligomer with six chiral centers usinga lanthanide(III) ion template. The oligomer folds aroundthe lanthanide ion to form an overhand knot complex ofsingle handedness. Subsequent joining of the overhand knotend groups by ring-closing olefin metathesis affords a singlestereoisomer of the trefoil knot in 90\% yield. The knot topologyand handedness was confirmed by NMR spectroscopy,mass spectrometry and X-ray crystallography. The pseudo-D3-symmetric knot was employed as an asymmetric catalystin Mukaiyama aldol reactions, generating enantioselectivitiesof up to 83:17 er, significantly higher than those obtainedwith a comparable unknotted ligand complex.",

author = "Guzman Gil-Ram{\'i}rez and Steven Hoekman and Kitching, \{Matthew O.\} and David Leigh and Inigo Vitorica-Yrezabal and Gen Zhang",

year = "2016",

doi = "10.1021/jacs.6b08421",

language = "English",

volume = "138",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "American Chemical Society",

number = "40",

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TY - JOUR

T1 - Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D3- Symmetric Trefoil Knot

AU - Gil-Ramírez, Guzman

AU - Hoekman, Steven

AU - Kitching, Matthew O.

AU - Leigh, David

AU - Vitorica-Yrezabal, Inigo

AU - Zhang, Gen

PY - 2016

Y1 - 2016

N2 - We report the stereoselective synthesis of aleft-handed trefoil knot from a tri(2,6-pyridinedicarboxamide) oligomer with six chiral centers usinga lanthanide(III) ion template. The oligomer folds aroundthe lanthanide ion to form an overhand knot complex ofsingle handedness. Subsequent joining of the overhand knotend groups by ring-closing olefin metathesis affords a singlestereoisomer of the trefoil knot in 90% yield. The knot topologyand handedness was confirmed by NMR spectroscopy,mass spectrometry and X-ray crystallography. The pseudo-D3-symmetric knot was employed as an asymmetric catalystin Mukaiyama aldol reactions, generating enantioselectivitiesof up to 83:17 er, significantly higher than those obtainedwith a comparable unknotted ligand complex.

AB - We report the stereoselective synthesis of aleft-handed trefoil knot from a tri(2,6-pyridinedicarboxamide) oligomer with six chiral centers usinga lanthanide(III) ion template. The oligomer folds aroundthe lanthanide ion to form an overhand knot complex ofsingle handedness. Subsequent joining of the overhand knotend groups by ring-closing olefin metathesis affords a singlestereoisomer of the trefoil knot in 90% yield. The knot topologyand handedness was confirmed by NMR spectroscopy,mass spectrometry and X-ray crystallography. The pseudo-D3-symmetric knot was employed as an asymmetric catalystin Mukaiyama aldol reactions, generating enantioselectivitiesof up to 83:17 er, significantly higher than those obtainedwith a comparable unknotted ligand complex.

U2 - 10.1021/jacs.6b08421

DO - 10.1021/jacs.6b08421

M3 - Article

SN - 0002-7863

VL - 138

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 40

ER -

Tying a Molecular Overhand Knot of Single Handedness and Asymmetric Catalysis with the Corresponding Pseudo-D3- Symmetric Trefoil Knot

Abstract

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CCDC 1494803: Experimental Crystal Structure Determination

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