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Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
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Highly efficient Ru(ii)-alkylidene based Hoveyda-Grubbs catalysts for ring-closing metathesis reactions
Mariam Y Al-Enezi1, Elizabeth John1, Yehia A Ibrahim1
1Department of Chemistry, Kuwait University P. O. Box 5969, Safat 13060 Kuwait n.alawadi@ku.edu.kw.
RSC Advances
|May 2, 2022
Summary
Three new phosphine-free ruthenium catalysts efficiently catalyze ring closing metathesis (RCM) reactions. The tosylated carbenoid (7b) demonstrated superior performance for various diene substrates, outperforming existing catalysts.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Organic Synthesis
Background:
- Ruthenium-alkylidene complexes are vital catalysts for olefin metathesis.
- Development of phosphine-free catalysts is crucial to avoid catalyst poisoning and improve stability.
- Ring closing metathesis (RCM) is a powerful tool for synthesizing cyclic compounds.
Purpose of the Study:
- To synthesize novel phosphine-free ruthenium-alkylidene catalysts.
- To evaluate their efficiency in ring closing metathesis (RCM) reactions.
- To compare their performance against established Grubbs catalysts.
Main Methods:
- Synthesis of three novel phosphine-free Ru-alkylidenes (7a-7c).
- Characterization using NMR, HRMS, and single crystal X-ray diffraction.
- Testing catalytic activity in RCM of various acyclic and macromolecular dienes.
Main Results:
- Successful synthesis and structural confirmation of Ru-alkylidenes 7a-7c.
- Tosylated carbenoid 7b exhibited the highest catalytic efficiency.
- Catalyst 7b effectively mediated RCM for diverse substrates, including N,N-diallylaniline derivatives and macromolecular dienes.
- High tolerance and efficiency observed with low catalyst loading (0.5-2.0 mol%).
Conclusions:
- Novel phosphine-free Ru-alkylidenes are efficient RCM catalysts.
- The tosylated carbenoid 7b is a highly effective catalyst, outperforming Grubbs (II) and Hoveyda-Grubbs (II) catalysts in specific applications.
- These findings offer a promising alternative for RCM reactions, particularly in challenging substrate systems.
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