Facile preparation of bicyclo[2.2.2]octenone derivatives via Diels–Alder cycloadditions of in situ-generated masked o-benzoquinones

Kalogiros, Christos; Hadjiarapoglou, Lazaros P.

doi:10.1016/j.tet.2011.03.018

Cited by 12 publications

(4 citation statements)

References 46 publications

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“…[19] Eugenol shows multidirectional biological effects [20] and is also widely used in dentistry. [21] As it possesses two highly reactive functional groups (carbon-carbon double bond and hydroxyl group), it has been also used intensively as a starting material in synthetic organic chemistry in a wide range of transformations i. e., substitution, [22] hydrogenation, [23] oxidation, [24] isomerization, [25] hydroalkoxylation, [26] thiol-ene click reaction, [27] atom transfer radical (ATR) addition, [28] 1,3-dipolar cycloaddition, [29] Diels-Alder reaction, [30] olefin crossmetathesis, [31] CÀ C bond-forming reactions [32] and polymerization. [33] To date, few articles focusing on the hydrosilylation of eugenol and its O-substituted derivatives have been published.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Bio‐Based Silane Coupling Agents by the Modification of Eugenol

et al. 2021

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A simple method for the synthesis of new bio-based silane coupling agents (SCAs) with a terpene aromatic core by the functionalization of cheap, natural eugenol and its sulfur derivatives using the hydrosilylation of the C=C bonds with HSi(OEt) 3 , followed by nucleophilic substitution reactions of OH/SH groups is presented. The obtained alkoxysilanes possess different polymerreactive functionalities (alkenyl, epoxide, thiirane, thiocarbamoyl, thioester, thioether moieties). This new group of biogenic SCAs was fully characterized using 1 H, 13 C, 29 Si NMR, FT-IR, GC-MS, and HRMS or elemental analysis. Examples of their application as additives to tire rubbers and their influence on several factors are also discussed.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Bio‐Based Silane Coupling Agents by the Modification of Eugenol

et al. 2021

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“…Once again, NOESY‐1D experiments have been key for assigning the correct diastereomer (see Figure S2 in the Supporting Information). The dienophilic character of C4–C5 double bond of o ‐quinone monoketals for self‐dimerizations and the high regio‐ and stereoselective control of this cycloaddition have been reported in the literature, however, to the best of our knowledge, these results are the first time they are described in oxidative dearomatization assays with coumarins.…”

Section: Resultsmentioning

confidence: 88%

Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran‐2‐one Aromaticity‐Mediated Regioselective Control and Biogenetic Implications

2020

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The synthetic feasibility of the oxidative cleavage: epoxidation of 7‐O‐geranylscopoletin followed by electrocyclic ring‐opening, proposed in the biogenesis of transtaganolides/basiliolides is studied. Unlike the proposed pericyclic reactions, this pathway has not yet been addressed. Three synthetic strategies have been tested consisting of: i) Baeyer–Villiger oxidation of p‐quinoids, ii) hydrolysis of quinone monoketals, or iii) direct fragmentation by using oxygen donors. Oxidation of the benzene ring of hydroxylated coumarins has been achieved using peroxyacids, but cleavage took place between undesired positions. The aromaticity conservation of the pyran‐2‐one cycle during oxidation is the controlling factor of these observed regioselectivities. The use of a 4,5‐dihydroxy‐2‐methoxycinnamate model, in which the pyran‐2‐one ring does not exert influence on oxidation, has allowed the design of a synthetic sequence toward an analogue of the natural pyran‐2‐one isolated from Thapsia transtagana, key in the biogenesis. Mechanistic proposals for the obtained results as well as their biogenetic implications are raised.

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“…An intermolecular variant of Diels–Alder reaction with two dienophiles, nitroethylene and vinyl phenyl sulfide, was also examined for the construction of the bicyclo[2.2.2]octan-2-one ring system of maoecrystal V (Scheme b). If successful, the nitro or phenylthio group could be removed by reduction under radical conditions …”

Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of (−)-Maoecrystal V by Enantiodetermining C–H Functionalization

et al. 2014

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The evolution of a program directed at the enantioselective total synthesis of maoecrystal V, a highly modified ent-kauranoid, is described. An early stage chiral auxiliary-directed asymmetric C–H functionalization for the construction of a key benzofuran intermediate enabled the first asymmetric synthesis of the natural enantiomer of maoecrystal V, confirming the assigned stereochemistry. A divergent course of the central intramolecular Diels–Alder reaction, which is dependent on the nature of the dienophile, initially led to the development of an unanticipated and previously unknown isomer of maoecrystal V, which we named maoecrystal ZG. In light of the reported selective and potent cytotoxic activity of maoecrystal V, the cytotoxic properties of maoecrystal ZG were also investigated.

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Facile preparation of bicyclo[2.2.2]octenone derivatives via Diels–Alder cycloadditions of in situ-generated masked o-benzoquinones

Cited by 12 publications

References 46 publications

Synthesis of Bio‐Based Silane Coupling Agents by the Modification of Eugenol

Synthesis of Bio‐Based Silane Coupling Agents by the Modification of Eugenol

Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran‐2‐one Aromaticity‐Mediated Regioselective Control and Biogenetic Implications

Enantioselective Synthesis of (−)-Maoecrystal V by Enantiodetermining C–H Functionalization

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