Photocycloadditions of Arenes Derived from Lignin

Desvals, Arthur; Baudron, Stéphane A.; Bulach, Véronique; Hoffmann, Norbert

doi:10.1021/acs.joc.1c01361

Cited by 9 publications

(3 citation statements)

References 69 publications

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“…Photochemical cycloadditions of lignin‐derived phenol compounds with alkenes ( 86 , Scheme 6) can also be considered to be driven by ESAA relief of the S 1 state benzene ring with the formation of photochemically more stable structure [179] . Under irradiation, vanillin carrying an alkene side chain can undergo intramolecular [2+2] photocycloaddition to form a nonaromatic tricyclic product 87 .…”

Section: Relief Of Esaamentioning

confidence: 99%

Photochemistry Driven by Excited‐State Aromaticity Gain or Antiaromaticity Relief

Yan

Slanina

Bergman

et al. 2023

Chemistry A European J

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Gain of aromaticity or relief of antiaromaticity along a reaction path are important factors to consider in mechanism studies. Analysis of such changes along potential energy surfaces has historically focused on reactions in the electronic ground state (S 0 ), but can also be used for excited states. In the lowest ππ* states, the electron counts for aromaticity and antiaromaticity follow Baird's rule where 4n π-electrons indicate aromaticity and 4n + 2 π-electrons antiaromaticity. Yet, there are also cases where Hückel's rule plays a role in the excited state. The electron count reversals of Baird's rule compared to Hückel's rule explain many altered physicochemical properties upon excitation of (hetero)annulene derivatives. Here we illustrate how the gain of excited-state aromaticity (ESA) and relief of excited-state antiaromaticity (ESAA) have an impact on photoreactivity and photostability. Emphasis is placed on recent findings supported by the results of quantum chemical calculations, and photoreactions in a wide variety of areas are covered.

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Section: Relief Of Esaamentioning

confidence: 99%

Photochemistry Driven by Excited‐State Aromaticity Gain or Antiaromaticity Relief

Yan

Slanina

Bergman

et al. 2023

Chemistry A European J

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“…Our recent results give new insights on the nature of the excited state involved in the first step of ortho photocycloaddition of benzonitrile derivatives (Scheme 13). [57] The irradiation of benzonitrile derivative 45 bearing a methoxy substituent revealed that the singlet excited state prevails by direct absorption in acetonitrile. On the one hand, the major products 46 and 47 are the result of a singlet state meta photocycloaddition.…”

Section: E-cd Complexmentioning

confidence: 99%

Photocycloadditions of benzene derivatives and their systematic application to organic synthesis

Desvals

Hoffmann

2023

Aust. J. Chem.

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Photocycloadditions of benzene derivatives with alkenes play an important role as key steps in organic synthesis. Intramolecular reactions have been most frequently studied in this context. Often, meta or [2 + 3] photocycloadditions take place in competition with ortho or [2 + 2] additions. The influence of the substitution pattern and the spin multiplicity of the excited state on the outcome of these reactions is discussed. A topological analysis permitting a systematic application of the [2 + 3] photocycloadditions to the total synthesis of natural products is presented and a selection of corresponding syntheses is discussed. More recently the [2 + 2] photocycloaddition and consecutive rearrangements on organic synthesis have been published. Some approaches in the context of asymmetric synthesis have also been reported.

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“…Such studies have also been performed in the context of the sustainable production of vanillin [ 90 , 91 ]. In the context of organic photochemical reactions, for example cycloaddition with alkenes, derivatives of this compound are particularly interesting because in such transformations a high degree of molecular complexity and diversity is generated without chemical activation and thus reducing waste production [ 27 , 92 , 93 , 94 ].…”

Section: Photocatalytic Transformations Of Biopolymersmentioning

confidence: 99%

Photocatalytic Transformation of Biomass and Biomass Derived Compounds—Application to Organic Synthesis

Fernandez

Hoffmann

2023

Molecules

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Biomass and biomass-derived compounds have become an important alternative feedstock for chemical industry. They may replace fossil feedstocks such as mineral oil and related platform chemicals. These compounds may also be transformed conveniently into new innovative products for the medicinal or the agrochemical domain. The production of cosmetics or surfactants as well as materials for different applications are examples for other domains where new platform chemicals obtained from biomass can be used. Photochemical and especially photocatalytic reactions have recently been recognized as being important tools of organic chemistry as they make compounds or compound families available that cannot be or are difficultly synthesized with conventional methods of organic synthesis. The present review gives a short overview with selected examples on photocatalytic reactions of biopolymers, carbohydrates, fatty acids and some biomass-derived platform chemicals such as furans or levoglucosenone. In this article, the focus is on application to organic synthesis.

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Photocycloadditions of Arenes Derived from Lignin

Cited by 9 publications

References 69 publications

Photochemistry Driven by Excited‐State Aromaticity Gain or Antiaromaticity Relief

Photochemistry Driven by Excited‐State Aromaticity Gain or Antiaromaticity Relief

Photocycloadditions of benzene derivatives and their systematic application to organic synthesis

Photocatalytic Transformation of Biomass and Biomass Derived Compounds—Application to Organic Synthesis

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