Exclusive Photodimerization Reactions of Chromone-2-carboxylic Esters Depending on Reaction Media

Sakamoto, Masami; Yagishita, Fumitoshi; Kanehiro, Masayuki; Kasashima, Yoshio; Mino, Takashi; Fujita, Tsutomu

doi:10.1021/ol101734k

Cited by 26 publications

(21 citation statements)

References 18 publications

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“…To achieve PP‐type asymmetric induction, the photochemical dimerization reaction of chromone was selected . Chromone (benzo‐γ‐pyrone) is the parent of a large number of naturally occurring compounds such as flavonoids and plant pigments and is also found in many pharmaceutical materials .…”

Section: Resultsmentioning

confidence: 99%

“…Recently, the photolysis of such chromonecarboxylic acid derivatives in fluid media was explored to give C 2 ‐symmetric anti ‐head‐to‐head ( anti ‐HH) dimers effectively and in excellent chemical yields from the triplet excited state. In this photoreaction, formation of four dimers was possible; however, only the C 2 ‐symmetric anti ‐HH dimers were exclusively produced (Scheme ) …”

Section: Resultsmentioning

confidence: 99%

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Asymmetric Synthesis Involving Reversible Photodimerization of a Prochiral Flavonoid Followed by Crystallization

et al. 2017

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Asymmetric synthesis involving photochemical dimerization of a prochiral flavonoid derivative in solution without any chiral source was achieved. Irradiation of ethyl 6‐bromochromonecarboxylate in solution efficiently gave a C2‐chiral anti‐head‐to‐head dimer in excellent chemical yield with good quantum efficiency (Φ365 = 0.15). X‐ray crystallographic analysis revealed that the dimer crystallized as a conglomerate of C2 space group. The crystalline dimer precipitated upon irradiation of the monomer in solution, and indirect racemization of the dimer through a reversible photoreaction in solution and selective crystallization simultaneously occurred to give the C2‐chiral dimer in optically active form with up to 80 % ee. Optically active photoproducts could be obtained by simply irradiating achiral materials in solution without an external chiral source.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Asymmetric Synthesis Involving Reversible Photodimerization of a Prochiral Flavonoid Followed by Crystallization

et al. 2017

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“…For example, benzene solution UV-irradiation of chromone produced anti-HT and trans-fused HT dimers in $1:1 ratio with 30% conversion and 99% yield [15]. The dimerization efficiency greatly depended upon the concentration of chromone [16]. Indeed, UV-irradiation of chromone-2-carboxylic esters (methyl, ethyl, or iso-propyl) in acetonitrile solutions produced anti-HH dimers from the triplet excited state while solid state reactions of methyl and iso-propyl chromone-2-carboxylic ester yielded the anti-HT dimers, and no solid state reaction was observed in ethyl derivative or for the parent chromone.…”

Section: Introductionmentioning

confidence: 99%

Modulating the reactivity of chromone and its derivatives through encapsulation in a self-assembled phenylethynylene bis-urea host

Salpage

Donevant

Smith

et al. 2016

Journal of Photochemistry and Photobiology A: Chemistry

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A B S T R A C TThis manuscript reports on the modulation of the photoreactivity of a series of chromones, also known as benzo-g-pyrones, by absorption into a porous self-assembled host formed from phenylethynylene bisurea macrocycles. Chromone and four derivatives namely 6-fluorochromone, 6-bromochromone, 7-hydroxy-4-chromone, and 3-cyanochromone are unreactive in the solid-state. Each of these derivatives was loaded into the nanochannels of self-assembled phenylethynylene bis-urea macrocycles to form solid hostÁguest complexes, which were subsequently UV-irradiated at room temperature under argon atmosphere. We observed that chromone and 6-fluorochromone underwent selective [2 + 2] photodimerization reactions to produce anti-HT dimers in high selectivity and conversion. The 6-bromochromone also reacted in high selectivity and conversion to afford an aryl coupling adduct. In each case, the products were extracted, and the crystalline host recovered. In comparison, 7-hydroxy-4-chromone, and 3-cyanochromone were unreactive within the complex. Simple GCMC simulation studies suggest that chromone, 6-fluorochromone, and 6-bromochromone were loaded in orientations that facilitate photoreaction, and correctly predicted that the anti-HT dimer would be favored in the chromone case. In contrast, syn-HH dimers were predicted by GCMC simulations for the halogen containing derivatives but were not observed. The simulations with 7-hydroxy-4-chromone were in agreement with the observed reactivity. We compare these computational and experimental findings and suggest future methods for optimizing simulation parameters. Our goal is to expand the scope and accuracy of the simulations to be able to predict the reactivity of guests encapsulated within columnar nanotubes.

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“…Masami Sakamoto et al (2010) described two examples of photodimerization of chromane derivatives in solution and solid state (Scheme 1). The irradiation of chromone-2-carboxylic esters 8 in solution phase resulted in the stereo-and regioselective formation of C 2 chiral anti-HH dimer 9 which is realized from the triplet excited state.…”

Section: Intermolecular Dimerizationmentioning

confidence: 99%

Photochemical studies: Chromones, bischromones and anthraquinone derivatives

Yusuf

Solanki

Jain

et al. 2019

Arabian Journal of Chemistry

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Photochemical reaction is a chemical reaction initiated by the absorption of energy in the form of light resulting in different types of reaction. Chromones, bischromones and anthraquinones are the bichromophoric molecules which contain the carbonyl group and double bond in conjugation. Photochemical reactions of these compounds result in the formation of such molecules which are not obtained via conventional methods. This review article describes the photochemical transformations of chromones, bischromones and anthraquinone derivatives and here main emphasis has been laid upon the intramolecular photochemical H-abstraction reactions that provide many exotic heterocyclics as the final photoproducts. ª 2014 Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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Exclusive Photodimerization Reactions of Chromone-2-carboxylic Esters Depending on Reaction Media

Cited by 26 publications

References 18 publications

Asymmetric Synthesis Involving Reversible Photodimerization of a Prochiral Flavonoid Followed by Crystallization

Asymmetric Synthesis Involving Reversible Photodimerization of a Prochiral Flavonoid Followed by Crystallization

Modulating the reactivity of chromone and its derivatives through encapsulation in a self-assembled phenylethynylene bis-urea host

Photochemical studies: Chromones, bischromones and anthraquinone derivatives

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