Bifunctional Molecular Photoswitches Based on Overcrowded Alkenes for Dynamic Control of Catalytic Activity in Michael Addition Reactions
| Autor: | Beatrice S. L. Collins, Ben L. Feringa, Stefano F. Pizzolato, Thomas van Leeuwen |
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| Přispěvatelé: | Synthetic Organic Chemistry, Basic and Translational Research and Imaging Methodology Development in Groningen (BRIDGE) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
CHEMICAL-REACTIONS
Substituent AMINE-THIOUREAS activity control 010402 general chemistry 01 natural sciences Catalysis chemistry.chemical_compound BETA-CYCLODEXTRIN ASYMMETRIC CATALYSIS Michael addition BAYLIS-HILLMAN REACTION Organic chemistry Moiety MOTORS Bifunctional molecular switches photoswitchable catalysts Amination Molecular switch chemistry.chemical_classification SWITCHABLE ORGANOCATALYST photochemistry ROTAXANE 010405 organic chemistry Alkene Organic Chemistry General Chemistry Combinatorial chemistry 0104 chemical sciences BOND DONORS LIGHT chemistry Organocatalysis Michael reaction |
| Zdroj: | Chemistry, 23(25), 6174-6184. Wiley-VCH Verlag GmbH & Co. KGaA |
| ISSN: | 1521-3765 0947-6539 |
| Popis: | The emerging field of artificial photoswitchable catalysis has recently shown striking examples of functional light-responsive systems allowing for dynamic control of activity and selectivity in organocatalysis and metal-catalysed transformations. While our group has already disclosed systems featuring first generation molecular motors as the switchable central core, a design based on second generation molecular motors is lacking. Here, the syntheses of two bifunctionalised molecular switches based on a photoresponsive tetrasubstituted alkene core are reported. They feature a thiourea substituent as hydrogen-donor moiety in the upper half and a basic dimethylamine group in the lower half. This combination of functional groups offers the possibility for application of these molecules in photoswitchable catalytic processes. The light-responsive central cores were synthesized by a Barton-Kellogg coupling of the prefunctionalized upper and lower halves. Derivatization using Buchwald-Hartwig amination and subsequent introduction of the thiourea substituent afforded the target compounds. Control of catalytic activity in the Michael addition reaction between (E)-3-bromo--nitrostyrene and 2,4-pentanedione is achieved upon irradiation of stable-(E) and stable-(Z) isomers of the bifunctional catalyst 1. Both isomers display a decrease in catalytic activity upon irradiation to the metastable state, providing systems with the potential to be applied as ON/OFF catalytic photoswitches. |
| Databáze: | OpenAIRE |
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