Light- and Thermal-Activated Olefin Metathesis of Hindered Substrates

Ivry, Elisa; Frenklah, Alexander; Ginzburg, Yakov; Levin, Efrat; Goldberg, Israel; Kozuch, Sebastian; Lemcoff, N. Gabriel; Tzur, Eyal

doi:10.1021/acs.organomet.7b00677

Cited by 36 publications

(27 citation statements)

References 47 publications

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“…An induction period can be seen, Fig. 3 and Fig S2 , which is common in similar metathesis reactions catalyzed by ruthenium complex 82 , 83 . This phenomenon occurs in both homogenous and heterogeneous systems.…”

Section: Resultsmentioning

confidence: 75%

Advanced sol–gel process for efficient heterogeneous ring-closing metathesis

Aharon

Meyerstein

Tzur

et al. 2021

Sci Rep

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Olefin metathesis, a powerful synthetic method with numerous practical applications, can be improved by developing heterogeneous catalysts that can be recycled. In this study, a single-stage process for the entrapment of ruthenium-based catalysts was developed by the sol–gel process. System effectiveness was quantified by measuring the conversion of the ring-closing metathesis reaction of the substrate diethyl diallylmalonate and the leakage of the catalysts from the matrix. The results indicate that the nature of the precursor affects pore size and catalyst activity. Moreover, matrices prepared with tetraethoxysilane at an alkaline pH exhibit a better reaction rate than in the homogenous system under certain reaction conditions. To the best of our knowledge, this is the first study to present a one-step process that is simpler and faster than the methods reported in the literature for catalyst entrapment by the sol–gel process under standard conditions.

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Section: Resultsmentioning

confidence: 75%

Advanced sol–gel process for efficient heterogeneous ring-closing metathesis

Aharon

Meyerstein

Tzur

et al. 2021

Sci Rep

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“…In comparison, an excellent yield of 98% was achieved with 3c. It is worth mentioning that 3c surpasses the reported activity of complex [Ru(SITol)(=CHPhSCF3)Cl2] (Tol-SCF3), 29 a latent chelating catalyst that can be activated thermally and by UV irradiation. Tol-SCF3 is able to achieve 83% conversion of 5 with 0.4 mol% under optimized conditions (0.1M toluene, 80 °C).…”

Section: Entrymentioning

confidence: 90%

“…Tol-SCF3 is able to achieve 83% conversion of 5 with 0.4 mol% under optimized conditions (0.1M toluene, 80 °C). 29 The reactivity difference between the complexes becomes more significant for products 7 and 9.…”

Section: Entrymentioning

confidence: 99%

Electronic effects in mixed N-heterocyclic carbene/phosphite indenylidene ruthenium metathesis catalysts

et al. 2019

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“…Elevated temperatures of operation can be paired with other factors, as in the work of Lemcoff and Tzur, who developed a series of S -chelated ruthenium catalysts that are thermal- and light-activated and that effectively catalyze the metathesis of hindered substrates. 20 …”

Section: Introductionmentioning

confidence: 99%

Sterically Tuned N-Heterocyclic Carbene Ligands for the Efficient Formation of Hindered Products in Ru-Catalyzed Olefin Metathesis

et al. 2020

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Formation of tetrasubstituted C–C double bonds via olefin metathesis is considered very challenging for classical Ru-based complexes. In the hope to improve this condition, three ruthenium olefin metathesis catalysts bearing sterically reduced N -heterocyclic carbene (NHC) ligands with xylyl “arms” were synthesized, characterized using both computational and experimental techniques, and tested in a number of challenging reactions. The catalysts are predicted to initiate much faster than the analogue with mesityl N -substituents. We also foreboded the rotation of xylyl side groups at ambient temperature and the existence of all four atropoisomers in the solution, which was in agreement with experimental data. These catalysts exhibited high activity at relatively low temperatures (45–60 °C) and at reduced catalyst loadings in various reactions of sterically hindered alkenes, including complex polyfunctional substrates of pharmaceutical interest, such as yangonin precursors, chrysantemic acid derivatives, analogues of cannabinoid agonists, α-terpineol, and finally a thermally unstable peroxide.

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Light- and Thermal-Activated Olefin Metathesis of Hindered Substrates

Cited by 36 publications

References 47 publications

Advanced sol–gel process for efficient heterogeneous ring-closing metathesis

Advanced sol–gel process for efficient heterogeneous ring-closing metathesis

Electronic effects in mixed N-heterocyclic carbene/phosphite indenylidene ruthenium metathesis catalysts

Sterically Tuned N-Heterocyclic Carbene Ligands for the Efficient Formation of Hindered Products in Ru-Catalyzed Olefin Metathesis

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