First Enantioselective Total Synthesis of Both (+)- and (−)-Metachromin A

Brüggemann, Markus; Holst, Christiane; Hoppe, Dieter

doi:10.1002/1099-0690(200102)2001:4<647::aid-ejoc647>3.0.co;2-6

Cited by 19 publications

(15 citation statements)

References 51 publications

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“…[29] Over the course of developing conditions for this transformation, Hoppe and coworkers found that a pseudoephedrine-derived oxazolidine ( 12 ) undergoes reaction with silyl enol ethers to afford α-substituted ketones. Remarkably, silyl enol ethers bearing aromatic substituents are alkylated with the opposite sense of diastereoselectivity relative to simpler aliphatic analogs ( 14 vs. 15, Scheme 5).…”

Section: Substrate–substrate Cation–π Interactionsmentioning

confidence: 99%

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The Cation–π Interaction in Small‐Molecule Catalysis

2016

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Catalysis by small molecules (≤ 1000 Da, 10−9 m) capable of binding and activating substrates via attractive, noncovalent interactions has emerged as an important approach in organic and organometallic chemistry. While the canonical noncovalent interactions—including hydrogen-bonding, ion-pairing, and π-stacking—have become mainstays of catalyst design, the cation–π interaction has been comparatively underutilized in this context since its discovery in the 1980s. However, like a hydrogen bond, the cation–π interaction exhibits a typical binding affinity of several kcal/mol with substantial directionality. These properties render it attractive as a design element for the development of small-molecule catalysts, and in recent years, the catalysis community has begun to take advantage of these features, drawing inspiration from pioneering research in molecular recognition and structural biology. This review surveys the burgeoning application of the cation–π interaction in catalysis.

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Section: Substrate–substrate Cation–π Interactionsmentioning

confidence: 99%

“…Remarkably, silyl enol ethers bearing aromatic substituents are alkylated with the opposite sense of diastereoselectivity relative to simpler aliphatic analogs ( 14 vs. 15, Scheme 5). [29e] …”

Section: Substrate–substrate Cation–π Interactionsmentioning

confidence: 99%

The Cation–π Interaction in Small‐Molecule Catalysis

2016

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“…In this particular example, desulfurization with RANEY s nickel led to reduction and isomerization of the carbon-carbon double bonds, Birch conditions gave either mono-desulfurization at À78 1C or reduction of the aromatic ring at higher temperature and preparation of the hydrazones led to degradation. 111…”

Section: Scheme 33mentioning

confidence: 99%

Thiols, thioethers, and related compounds as sources of C-centred radicals

2013

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Due to their stability, availability and reactivity, sulfides are particularly attractive sources of carbon-centered radicals. However, their reactivity in homolytic substitution processes is strongly reduced when compared with the corresponding selenides or halides. Despite this, sulfur-containing compounds can be engineered so that they become effective agents in radical chain reactions. A detailed description of the reactivity of organo-sulfur compounds is reported here with the aim of providing clear guidance on the scope and limitation of their use as radical precursors in chain reactions.

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“…It could be inferred, based on the previous data concerning structure-activity, that in this first screening the presence of the hydroquinonic segment would initially generate oxidative stress on the tested cells causing a significant raise on cell death related the presence of allyl alcohol and free hydroxyl moieties on the terpenic decalin rings, which possess a lower activity than diterpenhydroquinones had previously shown. Also the highest apoptotic effect of the compounds, which contain in their structure the hydroquinone segment, would promote the cytotoxic ability of the terpenic decalins due, probably, to the conjugated system present in the compounds 1 – 3 , analogous to the metachromins A-H series [ 29 ] which has shown a range of cytotoxic activities against murine leukemia cells and human epidermoid carcinoma cells [ 30 ].…”

Section: Resultsmentioning

confidence: 99%

Diterpenylhydroquinones from Natural ent-Labdanes Induce Apoptosis through Decreased Mitochondrial Membrane Potential

et al. 2013

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In this study, we examined the cytotoxic effects of seven ent-labdane derivatives 1–7 (0–100 μM) in different human cancer cell lines. Our results showed that compounds 1–3 exhibited significant dose-dependent inhibition on the growth of the three different human cell lines, according to the sulphorhodamine B assay and produced morphological changes consistent with apoptosis, as confirmed by Hoestch 3342 staining analysis. They induced apoptosis in various cancer cell lines, as shown by nuclear condensation and fragmentation and caspase 3 activation. Such induction was associated with the depletion of mitochondrial membrane potential. These activities led to the cleavage of caspases and the trigger of cell death process. Overall, the compounds showed potent proapoptotic effects on the two different cancer cell lines, suggesting that the compounds deserve more extensive investigation of their potential medicinal applications.

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First Enantioselective Total Synthesis of Both (+)- and (−)-Metachromin A

Cited by 19 publications

References 51 publications

The Cation–π Interaction in Small‐Molecule Catalysis

The Cation–π Interaction in Small‐Molecule Catalysis

Thiols, thioethers, and related compounds as sources of C-centred radicals

Diterpenylhydroquinones from Natural ent-Labdanes Induce Apoptosis through Decreased Mitochondrial Membrane Potential

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