Photochemical rearrangements in organic synthesis and the concept of the photon as a traceless reagent

Abstract

Many photochemical reactions are carried out under particular sustainable conditions. Often no chemical activation is necessary and the photon is considered as a traceless reagent. These reactions give access to unusual molecular structures and therefore are highly appreciated for application to organic synthesis, especially in heterocyclic chemistry. In this context, photochemical position isomerizations of heterocyclic compounds are discussed. Photochemical rearrangements induced by electron and hydrogen atom transfer (HAT) are also used for the preparation of heterocyclic compounds. Photochemical electrocyclization is discussed with sixmembered heterocycles such as pyridine derivatives. Finally, photochemically induced cyclization are presented as a very suitable method for the construction of heterocycles. The synthesis of biologically active compounds is particularly focused. Thus perspectives of sustainable chemistry are presented for the pharmaceutical and agrochemical industry.

Photochemistry in Pharmaceutical Development: A Survey of Strategies and Approaches to Industry-wide Implementation

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Tuning the selectivity of visible light-driven hydroxylation of benzene to phenol by using Cu, Fe and V oxides supported on N-doped TiO2

“…5 The majority of photocatalytic processes, both for the degradation of organic compounds and for the synthesis of organic products, are based on photoinduced charge transfer, which occurs at the interface of the semiconductor, the photogenerated electrons and holes, respectively, being primary reducing and oxidizing agents. [6][7][8] Photocatalytic reactions are commonly performed under UV light, 9 but suitable photocatalytic systems can also be activated by low-energy visible light, making available a powerful and sustainable route for organic synthesis and the production of valuable chemical compounds. 10 However, photocatalysis also presents some drawbacks, such as the low selectivity towards partial oxidation products, especially by using water as the solvent.…”

Photoinduced 6π-Electrocyclization of a 1,3,5-Hexatriene System Containing an Allomaltol Fragment

“…Photochemical processes are widely used in various fields of organic chemistry and technology . For example, the employing of UV-initiated reactions in total synthesis opens access to the preparation of complex natural products . In this case, diverse polyfunctional compounds can be obtained from easily available starting materials, wherein the photochemistry-based synthetic protocols generally do not require the application of toxic reagents.…”