Selenium‐Catalyzed Oxacyclization of Alkenoic Acids and Alkenols

Sancineto, Luca; Mangiavacchi, Francesca; Tidei, Caterina; Bagnoli, Luana; Marini, Francesca; Gioiello, Antimo; Ścianowski, Jacek; Santi, Claudio

doi:10.1002/ajoc.201700193

Cited by 41 publications

(15 citation statements)

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“…Wirth and co-workers have postulated facile alkene-to-alkene transfer of selenenium cations in the asymmetric reactions [60,63]. In the reports of Seleniranium species have been discussed for a long time as reactive intermediates in addition reactions of selenium-centered electrophiles to the double bond [57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74]. Some of them have been detected or isolated [57][58][59][71][72][73][74].…”

Section: Resultsmentioning

confidence: 99%

Remarkable Alkene-to-Alkene and Alkene-to-Alkyne Transfer Reactions of Selenium Dibromide and PhSeBr. Stereoselective Addition of Selenium Dihalides to Cycloalkenes

et al. 2020

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The original goal of this research was to study stereochemistry of selenium dihalides addition to cycloalkenes and properties of obtained products. Remarkable alkene-to-alkene and alkene-to-alkyne transfer reactions of selenium dibromide and PhSeBr were discovered during this research. The adducts of selenium dibromide with alkenes or cycloalkenes easily exchange SeBr2 with other unsaturated compounds, including acetylenes, at room temperature, in acetonitrile. Similar alkene-to-alkene and alkene-to-alkyne transfer reactions of the PhSeBr adducts with alkenes or cycloalkenes take place. The supposed reaction pathway includes the selenium group transfer from seleniranium species to alkenes or alkynes. It was found that the efficient SeBr2 and PhSeBr transfer reagents are Se(CH2CH2Br)2 and PhSeCH2CH2Br, which liberate ethylene, leading to a shift in equilibrium. The regioselective and stereoselective synthesis of bis(E-2-bromovinyl) selenides and unsymmetrical E-2-bromovinyl selenides was developed based on the SeBr2 and PhSeBr transfer reactions which proceeded with higher selectivity compared to analogous addition reactions of SeBr2 and PhSeBr to alkynes under the same conditions.

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Section: Resultsmentioning

confidence: 99%

Remarkable Alkene-to-Alkene and Alkene-to-Alkyne Transfer Reactions of Selenium Dibromide and PhSeBr. Stereoselective Addition of Selenium Dihalides to Cycloalkenes

et al. 2020

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“…Oxidations by H2O2 benefit from the presence of a catalyst and for this purpose organoselenides have proved particularly convenient. The combination of selenium and hydrogen peroxide is an efficient approach to different important classes of organic reactions, to which Bayer-Villiger oxidations of carbonylated substrates, i.e., aldehydes and ketones, oxidations of alcohols and nitrogen containing compounds and alkene epoxidations belong [1][2][3][4][5][6][7][8]. In the last decade, examples of this catalysis have been reported also in water, paving the route to the use of selenium in green chemistry and moving further apart from the use of toxic heavy metal compounds, like dichromates and permanganates [9,10].…”

Section: H2o2 Reduction By Organoselenidesmentioning

confidence: 99%

Selenium-Catalyzed Reduction of Hydroperoxides in Chemistry and Biology

Orian

Flohé

2021

Antioxidants

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Among the chalcogens, selenium is the key element for catalyzed H2O2 reduction. In organic synthesis, catalytic amounts of organo mono- and di-selenides are largely used in different classes of oxidations, in which H2O2 alone is poorly efficient. Biological hydroperoxide metabolism is dominated by peroxidases and thioredoxin reductases, which balance hydroperoxide challenge and contribute to redox regulation. When their selenocysteine is replaced by cysteine, the cellular antioxidant defense system is impaired. Finally, classes of organoselenides have been synthesized with the aim of mimicking the biological strategy of glutathione peroxidases, but their therapeutic application has so far been limited. Moreover, their therapeutic use may be doubted, because H2O2 is not only toxic but also serves as an important messenger. Therefore, over-optimization of H2O2 reduction may lead to unexpected disturbances of metabolic regulation. Common to all these systems is the nucleophilic attack of selenium to one oxygen of the peroxide bond promoting its disruption. In this contribution, we revisit selected examples from chemistry and biology, and, by using results from accurate quantum mechanical modelling, we provide an accurate unified picture of selenium’s capacity of reducing hydroperoxides. There is clear evidence that the selenoenzymes remain superior in terms of catalytic efficiency.

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“…The same reactivity can be translated into the oxidation of carbon-carbon double bonds, affording epoxide intermediates that can be opened by a nucleophilic solvent, affording vicinal diols [13,14] or α-methoxy alcohols [14] when the reaction is carried out in water or in methanol, respectively. When the substrate is an alkenol or an alkenoic acid, the epoxydic intermediate is opened intramolecularly by the internal nucleophile, leading to oxidative cyclofunctionalization with the formation of cyclic hydroxylethers or hydroxylactones [15]. Furthermore, the same catalytic system has been used also to oxidize aldehydes into their corresponding carboxylic acids in "on water" conditions, or into their corresponding esters when the reaction medium is a primary or a secondary alcohol [16].…”

Section: Introductionmentioning

confidence: 99%

Continuous Bioinspired Oxidation of Sulfides

et al. 2020

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A simple, efficient, and selective oxidation under flow conditions of sulfides into their corresponding sulfoxides and sulfones is reported herein, using as a catalyst perselenic acid generated in situ by the oxidation of selenium (IV) oxide in a diluted aqueous solution of hydrogen peroxide as the final oxidant. The scope of the proposed methodology was investigated using aryl alkyl sulfides, aryl vinyl sulfides, and dialkyl sulfides as substrates, evidencing, in general, a good applicability. The scaled-up synthesis of (methylsulfonyl)benzene was also demonstrated, leading to its gram-scale preparation.

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Selenium‐Catalyzed Oxacyclization of Alkenoic Acids and Alkenols

Abstract: A general and efficient method for the selenium‐catalyzed cyclofunctionalization reaction of alkenoic acids and alkenols is presented. Hydrogen peroxide was used as the green oxidant and all of the products were obtained in very good yields.

Cited by 41 publications

References 50 publications

Remarkable Alkene-to-Alkene and Alkene-to-Alkyne Transfer Reactions of Selenium Dibromide and PhSeBr. Stereoselective Addition of Selenium Dihalides to Cycloalkenes

Remarkable Alkene-to-Alkene and Alkene-to-Alkyne Transfer Reactions of Selenium Dibromide and PhSeBr. Stereoselective Addition of Selenium Dihalides to Cycloalkenes

Selenium-Catalyzed Reduction of Hydroperoxides in Chemistry and Biology

Continuous Bioinspired Oxidation of Sulfides

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