Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

Bachollet, Sylvestre P. J. T.; Terao, Ken; Aida, Shin; Nishiyama, Yasuhiro; Kakiuchi, Kiyomi; Oelgemöller, Michael

doi:10.3762/bjoc.9.237

Cited by 24 publications

(13 citation statements)

References 46 publications

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“…2(5 H )-furanones (butenolides)] have long been in the center of interest as they behave relatively well both in inter- and intramolecular [2 + 2] photocycloaddition reactions. 519 A substituent in the 5-position creates a stereogenic center, and studies on the facial diastereoselectivity of the respective 5-substituted 2(5 H )-furanones commenced in the late 1980s. Initial work on 5-alkyl-2(5 H )-furanones was performed by the groups of Koga 520 and Font, 521 − 523 while 5-alkoxy-2(5 H )-furanones were investigated by Scharf, Hoffmann, and co-workers.…”

Section: Direct Excitation and Sensitizationmentioning

confidence: 99%

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

et al. 2016

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The [2 + 2] photocycloaddition is undisputedly the most important and most frequently used photochemical reaction. In this review, it is attempted to cover all recent aspects of [2 + 2] photocycloaddition chemistry with an emphasis on synthetically relevant, regio-, and stereoselective reactions. The review aims to comprehensively discuss relevant work, which was done in the field in the last 20 years (i.e., from 1995 to 2015). Organization of the data follows a subdivision according to mechanism and substrate classes. Cu(I) and PET (photoinduced electron transfer) catalysis are treated separately in sections 2 and 4, whereas the vast majority of photocycloaddition reactions which occur by direct excitation or sensitization are divided within section 3 into individual subsections according to the photochemically excited olefin.

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Section: Direct Excitation and Sensitizationmentioning

confidence: 99%

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

et al. 2016

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“…Furthermore, extremely small characteristic dimensions of microreactors ensure excellent light irradiation of the entire reaction medium and thus provide an irradiation homogeneity, resulting in higher reaction selectivity, shorter reaction times, and lower catalyst loadings . Microreactors have been extensively applied for various gas‐liquid photochemical processes, such as cycloadditions, trifluoromethylations, and singlet oxygen oxidations …”

Section: Introductionmentioning

confidence: 99%

A compact photomicroreactor design for kinetic studies of gas‐liquid photocatalytic transformations

Hessel

Noël

2015

AIChE Journal

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A compact photomicroreactor assembly consisting of a capillary microreactor and small-scale LEDs was developed for the study of reaction kinetics in the gas-liquid photocatalytic oxidation of thiophenol to phenyl disulfide within Taylor flow. The importance of photons was convincingly shown by a suction phenomenon due to the fast consumption of oxygen.Mass transfer limitations were evaluated and an operational zone without mass transfer effects was chosen to study reaction kinetics. Effects of photocatalyst loading and light sources on the reaction performance were investigated. Reaction kinetic analysis was performed to obtain reaction orders with respect to both thiophenol and oxygen based on

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“…Many laboratory systems use commercially available 'embedded' flow reactors, pumping systems and light sources [23][24][25][26]. Due to their flexible design, microcapillary reactors have recently become more widespread [27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Photochemically induced radical reactions with furanones

Oelgemöller

Hoffmann

2015

Pure and Applied Chemistry

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Radicals are easily generated via hydrogen transfer form secondary alcohols or tertiary amines using photochemical sensitization with ketones. They can subsequently add to the electron deficient double bond of furanones. The addition of the alcohols is particularly efficient. Therefore, this reaction was used to characterize and to compare the efficiency of different photochemical continuous flow microreactors. A range of micro-structured reactors were tested and their performances evaluated. The enclosed microchip enabled high space-time-yields but its microscopic dimensions limited its productivity. In contrast, the open microcapillary model showed a greater potential for scale-up and reactor optimization. A 10-microcapillary reactor was therefore constructed and utilized for typical R&D applications. Compared to the corresponding batch processes, the microreactor systems gave faster conversions, improved product qualities and higher yields. Similar reactions have also been carried out with electronically excited furanones and other α,β-unsaturated ketones. In this case, hydrogen is transferred directly to the excited olefin. This reaction part may occur either in one step, i.e., electron and proton are transferred simultaneously, or it may occur in two steps, i.e., the electron is transferred first and the proton follows. In the first case, a C-C bond is formed in the α position of the α,β-unsaturated carbonyl compound and in the second case this bond is formed in the β position. For the first reaction, the influence of stereochemical elements of the substrate on the regioselectivity of the hydrogen abstraction on the side chain has been studied.

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Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

Cited by 24 publications

References 46 publications

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

A compact photomicroreactor design for kinetic studies of gas‐liquid photocatalytic transformations

Photochemically induced radical reactions with furanones

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Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

Cited by 24 publications

References 46 publications

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

A compact photomicroreactor design for kinetic studies of gas‐liquid photocatalytic transformations

Photochemically induced radical reactions with furanones

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Product

Resources

About

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions

Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions