Origin of Chiral Induction in Radical Reactions with the Diastereoisomers (5R)- and (5S)-5-l-Menthyloxyfuran-2[5H]-one

Marinković, Siniša; Brulé, Cédric; Hoffmann, Norbert; Prost, Élise; Nuzillard, Jean‐Marc; Bulach, Véronique

doi:10.1021/jo030292x

Cited by 48 publications

(41 citation statements)

References 64 publications

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“…[18,19,30,34,35] In general, the simple a functionalisation of such compounds, for example in the case of the BaylisHillman [34,36] reaction, is more complex. Recently, a similar Lewis acid catalysed reaction was published.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Triplet‐Sensitised Radical Reactions of Furanone Derivatives

Jahjah

Gassama

Bulach

et al. 2010

Chemistry A European J

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The stereo- and regioselectivity of triplet-sensitised radical reactions of furanone derivatives have been investigated. Furanones 7a,b were excited to the (3)pipi* state by triplet energy transfer from acetone. Intramolecular hydrogen abstraction then occurred such that hydrogen was transferred from the tetrahydropyran to the beta position of the furanone moiety. Radical combination of the tetrahydropyranyl and the oxoallyl radicals led to the final products 8a,b. In the intramolecular reaction, overall, a pyranyl group adds to the alpha position of the furanone. The effect of conformation was first investigated with compounds 9a,b carrying an additional substituent on the tether between the furanone and pyranyl moiety. Further information on the effect of conformation and the relative configuration at the pyranyl anomeric centre and the furanone moiety was obtained from the transformations of the glucose derivatives 12, 14, 17 and 18. Radical abstraction occurred at the anomeric centre and at the 5'-position of the glucosyl moiety. Computational studies of the hydrogen-abstraction step were carried out with model structures. The activation barriers of this step for different stereoisomers and the abstraction at the anomeric centre and at the 6'-position of the tetrahydropyranyl moiety were calculated. The results of this investigation are in accordance with experimental observations. Furthermore, they reveal that the reactivity and regioselectivity are mainly determined in the hydrogen-abstraction step. Intramolecular hydrogen abstraction (almost simultaneous electron and proton transfer) in (3)pipi* excited furanones only takes place under restricted structural conditions in a limited number of conformations that are defined by the relative configuration of the substrates. It is observed that in the biradical intermediate, back-hydrogen transfer occurs leading to the starting compound. In the case of glucose derivatives, this reaction led to epimerisation at the anomeric centre.

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Section: Introductionmentioning

confidence: 99%

Stereoselective Triplet‐Sensitised Radical Reactions of Furanone Derivatives

Jahjah

Gassama

Bulach

et al. 2010

Chemistry A European J

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“…The radical addition occurred stereospecifically anti with respect to the alkoxy substituent (relative configuration at centers 4 and 5). [17] The configuration in the a position of the nitrogen atom of the resulting aminolactones 13 a,b,c was not completely controlled. Therefore, two diastereomers were obtained (compare [20,21] and Table 2).…”

Section: Resultsmentioning

confidence: 99%

“…[7,16] We have efficiently performed this transformation by applying the classical procedure using UV light and rose bengale as sensitizer. [17] Tertiary amines carrying long alkyl chains were chosen as the hydrophobic moieties of the surfactants. These compounds have been synthesized using reductive amination from the secondary amines pyrrolidine and piperidine and fatty aldehydes.…”

Section: Resultsmentioning

confidence: 99%

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Photochemical Key Steps in the Synthesis of Surfactants from Furfural‐Derived Intermediates

Gassama

Ernenwein²,

Hoffmann

2009

ChemSusChem

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Furfural is oxidized to 2[5H]-furanone by using hydrogen peroxide or to 5-hydroxy-2[5H]-furanone by using photo-oxygenation. An amine function is introduced by photochemically induced radical addition of tertiairy amines, some of which carry an n-alkyl side chain as hydrophobic moiety. These amines are produced from fatty aldehydes and cyclic secondary amines. The resulting adducts are transformed into amphoteric surfactants possessing an ammonium and a carboxylate function. Amphoteric (pK(N) and isoelectric point) and surfactant properties such as the critical micelle concentration and the adsorption efficiency are determined.

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“…10) [24] . 上述芳香胺光化学反应生成的手性四氢喹啉衍生物(如化合物 35a), 可进一步衍生而应用于药物合成 [24] ; 特别是在同样的条件下, 化合物 14 的异构体 38 也可发生类似的光化学反应 [25] [54] (Scheme 20). 另外, α,β-不饱和内酯光化学反应的复杂性, 不仅体现在可发生各种光化学环加成反应, 而且某些更多共轭结构的 α,β-不饱和内酯(如化合物 89)在光照下还可通过电环化而发生开环和缩环两种竞争反应, 甚至继续发生光化学降解等系列反应 [55,56] (Scheme 21).…”

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