Issue 6, 2020

Rational synthesis of interpenetrated 3D covalent organic frameworks for asymmetric photocatalysis

Abstract

Covalent organic frameworks (COFs) show great promise as heterogeneous photocatalysts, but they have not yet been explored for asymmetric photocatalysis, which is important for the sustainable production of pharmaceuticals and fine chemicals. We report here a pair of twofold interpenetrated 3D COFs adopting a rare (3,4)-connected ffc topology for photocatalytic asymmetric reactions by imine condensation of rectangular and trigonal building blocks. Both COFs containing a photoredox triphenylamine moiety are efficient photocatalysts for the cross-dehydrogenative coupling reactions and asymmetric α-alkylation of aldehydes integrated with a chiral imidazolidinone catalyst. Under visible-light irradiation, the targeted chiral products are produced in satisfactory yields with up to 94% enantiomeric excess, which are comparable to those of reported reactions using molecular metal complexes or organic dyes as photosensitizers. Whereas the COFs became amorphous after catalysis, they can be recrystallized through solvent-assisted linker exchange and reused without performance loss. This is the first report utilizing COFs as photocatalysts to promote enantioselective photochemical reactions.

Graphical abstract: Rational synthesis of interpenetrated 3D covalent organic frameworks for asymmetric photocatalysis

Supplementary files

Article information

Article type
Edge Article
Submitted
27 sep. 2019
Accepted
17 dic. 2019
First published
19 dic. 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2020,11, 1494-1502

Rational synthesis of interpenetrated 3D covalent organic frameworks for asymmetric photocatalysis

X. Kang, X. Wu, X. Han, C. Yuan, Y. Liu and Y. Cui, Chem. Sci., 2020, 11, 1494 DOI: 10.1039/C9SC04882K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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