Synthesis of Oxygen- and Nitrogen-Containing Heterocycles by Ring-Closing Metathesis

Deiters, Alexander; Martin, Stephen F.

doi:10.1021/cr0200872

Cited by 1,274 publications

(332 citation statements)

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“…Alkaloids are a group of ring structure nitrogen containing organic compounds with a wide range of anticancer activity (60). These compounds take part in cancer inhibition via prevention of enzyme topoisomerase activity which is involved in DNA imitation, inducing apoptosis and expression of p53 gene (61,62).…”

Section: Alkaloidsmentioning

confidence: 99%

Phytochemicals in Cancer Prevention: A Review of the Evidence

et al. 2017

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Context: Cancer generally is considered as a neoplastic disease with particular causative and etiologic factors as well as protective elements. Although it has remained difficult to treat, it is preventable. Recently, the interest in dietary phytochemicals intake has considerably increased for potential cancer chemoprevention.Evidence Acquisition: This report reviews the role of phytochemical consumption in cancer prevention based on publications from PubMed, Science direct, Google Scholar, and Scopus from the year 1996 onward using cancer, chemoprevention, phytochemical keywords.Results: Regular intake of phytochemicals has been demonstrated to prevent cancer during its different stages including initiation, promotion and progression. Considering the animal models, the second step is the main stage for cancer chemoprevention. Conclusions:The phytochemicals involved in chemoprevention can be categorized in different groups naming phenolics, carotenoid, alkaloids, organosulfur compounds and nitrogen-containing compounds. They are able to stop, postpone and reverse carcinogenesis by different mechanisms.

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Section: Alkaloidsmentioning

confidence: 99%

Phytochemicals in Cancer Prevention: A Review of the Evidence

et al. 2017

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“…In addition, when bulkier olefins than ethylene are involved in the 21 18 metathesis, the possibility of an activation step through an associative-1 displacement mechanism as suggested for Hoveyda-Grubbs catalysts was 2 ruled out [77]. The energies associated with complexes in which 3 coordination of ethylene prior to dissociation of a phosphite ligand was 4 involved were found too high to be reasonable.…”

Section: Mechanistic Investigation 16mentioning

confidence: 99%

“…In the 7 trans isomers, values obtained for the phosphite (14.6 kcal/mol) were 8 smaller than for the phosphane (22.3 kcal/mol), showing that the less 9 donating P(OMe) 3 should dissociate more rapidly than PMe 3 . However, in 10 the cis isomer, the BDE values for P(OMe) 3 (21.8 kcal/mol) were higher 11 In addition, when bulkier olefins than ethylene are involved in the 21 metathesis, the possibility of an activation step through an associative-1 displacement mechanism as suggested for Hoveyda-Grubbs catalysts was 2 ruled out [77]. The energies associated with complexes in which 3 coordination of ethylene prior to dissociation of a phosphite ligand was 4 involved were found too high to be reasonable.…”

Section: Mechanistic Investigation 16mentioning

confidence: 99%

Phosphite ligands in Ru-based olefin metathesis catalysts

Bantreil

Cazin

2015

Monatsh Chem

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Olefin metathesis represents one of the most important tools in 9 organometallic chemistry and catalysis [1][2][3][4][5][6][7]. Its relevance is highlighted 10 by its increasing importance at the industrial level. In addition, the award of 11 the Nobel Prize in 2005 to Y. Chauvin, R. H. Grubbs and R. R. Schrock for 12 their respective involvement in the discovery of olefin metathesis, 13showcases its significance [8][9][10]. Since their pioneering work on 14 molybdenum (Schrock) and ruthenium (Grubbs) catalysts, numerous 15 studies have been performed to enhance the activity and lifetime of the 16 catalysts. Despite the importance of the molybdenum chemistry [11, 12], 17 this review will focus on the development of ruthenium complexes as they 18 have shown to be more user-friendly, thus far. 19Since the discovery of a ruthenium vinylcarbene complex able to 20 catalyze the olefin metathesis reaction in 1992 [13], several developments 21 have led to ever more efficient catalysts. In particular, the introduction of a 22 benzylidene moiety led to the well-known Grubbs first-generation catalyst 23 NHCs have received significant attention as organocatalysts and ancillary 11 transition metal ligands. Indeed, these strongly σ-donating ligands 12 represent suitable replacements for tertiary phosphanes in numerous 13 organometallic complexes [22]. Diversification of their structure is 14 convenient and allows for the generation of families of tunable ligands in 15 terms of sterics and electronics. In ruthenium-catalyzed olefin metathesis, 16 the introduction of NHCs has had a critical and direct impact on catalyst 17 stability and efficiency, giving rise to second-generation catalysts [23][24][25]. Another possibility to enhance catalysts stability and activity was to 6 tune the so-called throwaway ligand. Numerous studies have been reported 7 on the substitution of the commonly used tricyclohexylphosphine by other 8 phosphanes [26][27][28][29], NHCs [30][31][32][33], pyridine [18, 34], and Schiff bases 9 [35][36][37] in the benzylidene and indenylidene families. The search for even 10 more stable and efficient catalysts led to studies based on the known 11 synergistic effect between strongly σ donating NHCs and strongly π acidic 12 phosphites on transition metals [38][39][40][41]. This short review will present and 13 discuss the synthesis of this new family of ruthenium NHC/phosphite 14 complexes, their catalytic efficiency and summarize mechanistic insights 15 into their stability and reactivity. 16 17 Synthesis of ruthenium NHC phosphites complexes 18As stated above, the original thoughts behind these novel complexes were 19 to combine phosphites and NHC ligands around a ruthenium center to 20 obtain unreported structures. Consequently, several ruthenium complexes 21 were synthesized, featuring various phosphites and NHCs in the 1 benzylidene and indenylidene series. In addition, the specific properties of 2 NHC/phosphite ruthenium complexes allowed for the generation of a 3 highly interesting cationic species via hal...

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“…While the para-substituent on the aromatic ring was changed, entry 3 and 5 show that a switch from E to Z starting materials lead to a switch in enantiomers, which is likely to be an expression of the change in chirality of the products: E starting material are predicted to yield 55 an S product, and conversely Z an R product. …”

Section: 1-diaryl and 112-triarylsmentioning

confidence: 99%

Iridium catalysis: application of asymmetric reductive hydrogenation

Cadu

Andersson

2013

Dalton Trans.

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PostprintThis is the accepted version of a paper published in Dalton Transactions. This paper has been peerreviewed but does not include the final publisher proof-corrections or journal pagination. Iridium, despite being one of the least abundant transition metals, has known several uses. N,P-ligated 5 iridium catalysts are used to perform many highly selective reactions. These methodologies have been developed extensively over the past 15 years. More recently, the application of iridium N,P catalysts in asymmetric hydrogenation has been a focus, to find novel applications and to expand on their current synthetic utility. The aim of this perspective is to highlight the advances made by the Andersson group.

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Synthesis of Oxygen- and Nitrogen-Containing Heterocycles by Ring-Closing Metathesis

Cited by 1,274 publications

References 265 publications

Phytochemicals in Cancer Prevention: A Review of the Evidence

Phytochemicals in Cancer Prevention: A Review of the Evidence

Phosphite ligands in Ru-based olefin metathesis catalysts

Iridium catalysis: application of asymmetric reductive hydrogenation

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