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Radical‐involved multicomponent difunctionalization of 1,3‐dienes has recently emerged as a promising strategy for rapid synthesis of valuable allylic compounds in one‐pot operation. However, the expansion of radical scope and enantiocontrol remain two major challenges. Herein, we describe an unprecedented photoinduced copper‐catalyzed highly enantioselective three‐component radical 1,2‐azidooxygenation of 1,3‐dienes with readily available azidobenziodazolone reagent and carboxylic acids. This mild protocol exhibits a broad substrate scope, high functional group tolerance, and exceptional control over chemo‐, regio‐ and enantioselectivity, providing practical access to diverse valuable azidated chiral allylic esters. Mechanistic studies imply that the chiral copper complex is implicated as a bifunctional catalyst in both the photoredox catalyzed azidyl radical generation and enantioselective radical C−O cross‐coupling. [ABSTRACT FROM AUTHOR]

The exploration of value‐added conversions of naturally abundant amino acids has received considerable attention from the synthetic community. Compared with the well‐established asymmetric decarboxylative transformation, the asymmetric deaminative transformation of amino acids still remains a formidable challenge, mainly due to the lack of effective strategies for the C−N bond activation and the potential incompatibility with chiral catalysts. Here, we disclose a photoinduced Cu‐catalyzed asymmetric deaminative coupling reaction of amino acids with arylboronic acids. This new protocol provides a series of significant chiral phenylacetamides in generally good yields and excellent stereoselectivity under mild and green conditions (42–85 % yields, up to 97 % ee). Experimental investigations and theoretical calculations were performed to reveal the crucial role of additional phenols in improving catalytic efficiency and enantiocontrol. [ABSTRACT FROM AUTHOR]

A green and sustainable nitrone formation reaction via visible-light-promoted reaction of aryl diazoacetates with nitrosoarenes is described. This protocol exhibits good functional group tolerance and broad substrate scope for both aryl diazoacetates with nitrosoarenes. Comparing the reported methods for the synthesis of nitrones from nitrosoarenes, the reaction described herein occurs under sole visible-light irradiation without the need of any catalysts and additives. [ABSTRACT FROM AUTHOR]

Visible-light-driven organic photochemical reactions have attracted substantial attention from the synthetic community. Typically, catalytic quantities of photosensitizers, such as transition metal complexes, organic dyes, or inorganic semiconductors, are necessary to absorb visible light and trigger subsequent organic transformations. Recently, in contrast to these photocatalytic processes, a variety of photocatalyst-free organic photochemical transformations have been exploited for the efficient formation of carbon–carbon and carbon–heteroatom bonds. In addition to not requiring additional photocatalysts, they employ low-energy visible light irradiation, have mild reaction conditions, and enable broad substrate diversity and functional group tolerance. This review will focus on a summary of representative work in this field in terms of different photoexcitation modes. 1 Introduction 2 Visible Light Photoexcitation of a Single Substrate 3 Visible Light Photoexcitation of Reaction Intermediates 4 Visible Light Photoexcitation of EDA Complexes between Substrates 5 Visible Light Photoexcitation of EDA Complexes between Substrates and Reaction Intermediates 6 Visible Light Photoexcitation of Products 7 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Alkene bifunctionalizations are powerful tools for the rapid construction of structurally complex and valuable scaffolds, and such reactions typically involve the use of transition‐metal catalysts or organocatalysts. Here, we report for the first time a photogenerated neutral nitrogen radical catalyzed intermolecular alkene bifunctionalization by using allyl sulfones as the source of both the carbon and the sulfone functionalities under mild conditions. The key to the success of this protocol involves the visible‐light‐mediated photocatalytic in situ generation of a nitrogen‐centered radical from the N‐(2‐acetylphenyl) benzenesulfonamide catalyst, and its activation of the allyl sulfones to generate reactive species. The preliminary control experiments supported the postulated mechanism. [ABSTRACT FROM AUTHOR]

Visible‐light photocatalysis is a rapidly developing and powerful strategy to initiate organic transformations, as it closely adheres to the tenants of green and sustainable chemistry. Generally, most visible‐light‐induced photochemical reactions occur through single‐electron transfer (SET) pathways. Recently, visible‐light‐induced energy‐transfer (EnT) reactions have received considerable attentions from the synthetic community as this strategy provides a distinct reaction pathway, and remarkable achievements have been made in this field. In this Review, we highlight the most recent advances in visible‐light‐induced EnT reactions. Making light of synthesis: The distinctive reaction pathways provided by visible‐light‐induced energy transfer (EnT) has resulted in it receiving considerable attention. This Review discusses the most recent advances in visible‐light‐induced EnT reactions. [ABSTRACT FROM AUTHOR]

Abstract: The control of selectivity in the reactions of the highly reactive open‐shell carbon radicals is an attractive but often challenging task. Building on the strategy of photoinduced iminyl radical‐mediated C−C bond cleavage, we have developed photocatalytic neophyl rearrangement and reduction of distal carbon radicals under visible light irradiation of O‐acyl oximes. This mild protocol tolerates a wide range of readily available O‐acyl oximes, enabling facile synthesis of diversely substituted α,β‐unsaturated nitriles and β‐functionalized saturated nitriles in a highly selective manner. [ABSTRACT FROM AUTHOR]

Abstract: A room‐temperature, visible‐light‐driven N‐centered iminyl radical‐mediated and redox‐neutral C−C single bond cleavage/radical addition cascade reaction of oxime esters and unsaturated systems has been accomplished. The strategy tolerates a wide range of O‐acyl oximes and unsaturated systems, such as alkenes, silyl enol ethers, alkynes, and isonitrile, enabling highly selective formation of various chemical bonds. This method thus provides an efficient approach to various diversely substituted cyano‐containing alkenes, ketones, carbocycles, and heterocycles. [ABSTRACT FROM AUTHOR]

A visible-light-driven radical-mediated strategy for the in situ generation of aza- ortho-quinone methides from 2-vinyl-substituted anilines and alkyl radical precursors is described. This process enables an efficient multicomponent reaction of 2-vinylanilines, halides, and sulfur ylides, and has a wide substrate scope and good functional group tolerance. Treatment of the cycloaddition products with a base leads to densely functionalized indoles in a single-flask operation. [ABSTRACT FROM AUTHOR]

An efficient visible light photocatalytic and external oxidant-free N-radical 5-exo cyclization/addition/aromatization cascade of β,γ-unsaturated hydrazones is described, which provides a practical route to various biologically interesting dihydropyrazole-fused benzosultams in satisfactory yields. [ABSTRACT FROM AUTHOR]

Bicarbonyl-substituted sulfur ylide is a useful, but inert reagent in organic synthesis. Usually, harsh reaction conditions are required for its transformation. For the first time, it was demonstrated that a new, visible-light photoredox catalytic annulation of sulfur ylides under extremely mild conditions, permits the synthesis of oxindole derivatives in high selectivities and efficiencies. The key to its success is the photocatalytic single-electron-transfer (SET) oxidation of the inert amide and acyl-stabilized sulfur ylides to reactive radical cations, which easily proceeds with intramolecular C−H functionalization to give the final products. [ABSTRACT FROM AUTHOR]

Radicals are an important class of versatile and highly reactive species. Compared with the wide applications of various C-centred radicals, however, the N-radical species including N-centred radicals and radical ions remain largely unexplored due to the lack of convenient methods for their generation. In recent years, visible light photoredox catalysis has emerged as a powerful platform for the generation of various N-radical species and methodology development towards the synthesis of diverse N-containing compounds. In this tutorial review, we highlight recent advances in this rapidly developing area with particular emphases put on the working models and new reaction design. [ABSTRACT FROM AUTHOR]

Visible-light-induced radical decarboxylative functionalization of carboxylic acids and their derivatives has recently received considerable attention as a novel and efficient method to create C-C and C-X bonds. Generally, this visible-light-promoted decarboxylotion process can smoothly occur under mild reaction conditions with a broad range of substrates and an excellent functional-group tolerance. The radical species formed from the decarboxy lotion step can participate in not only single photocatalytic transformations, but also dual-catalytic cross-coupling reactions by combining photoredox catalysis with other catalytic processes. Recent advances in this research area are discussed herein. [ABSTRACT FROM AUTHOR]

Visible-light-induced photocatalytic decarboxylative alkynylations of carboxylic acids have been developed for the first time. The reaction features extremely mild conditions, broad substrate scope, and avoids additional oxidants. Importantly, a decarboxylative carbonylative alkynylation has also been carried out in the presence of carbon monoxide (CO) under photocatalytic conditions, which affords valuable ynones in high yields at room temperature. [ABSTRACT FROM AUTHOR]

A visible light photocatalytic arylation-lactonization sequence has been developed for the synthesis of γ,γ-disubstituted butyrolactones. This unprecedented transformation features simple experimental procedures under very mild conditions. A one-step synthesis of isobenzofuran-1(3 H)-one has been carried out to demonstrate the synthetic application of this reaction. [ABSTRACT FROM AUTHOR]

A photocatalytic formal [3+2] cycloaddition of 2 H-azirines with alkynes has been achieved under irradiation by visible light in the presence of organic dye photocatalysts. This transformation provides efficient access to highly functionalized pyrroles in good yields and has been applied to the synthesis of drug analogues. A primary trial of photocascade catalysis merging energy transfer and redox neutral reactions was shown to be successful. [ABSTRACT FROM AUTHOR]

A novel method for the synthesis of 1,4-diketones from β-ketosulfones was developed by means of a visible light-induced CS bond activation process. Symmetrical and unsymmetrical 1,4-diketones can be easily prepared in moderate to good yields. [ABSTRACT FROM AUTHOR]

Carbocyclic and heterocyclic ring systems are important structural architectures in many bioactive natural products, as well as in a variety of fine chemicals. The utilization of visible-light photocatalytic strategies to construct these ring systems has received considerable attention in the past few years. This microreview presents a brief summary of the use of visible-light photoredox catalytic strategies for the synthesis of carbocyclic and heterocyclic targets. [ABSTRACT FROM AUTHOR]

Visible-light photoredox catalysis has attracted tremendous interest within the synthetic community. As such, the activation mode potentially provides a more sustainable and efficient platform for the activation of organic molecules, enabling the invention of many controlled radical-involved reactions under mild conditions. In this context, amide synthesis via the strategy of photoredox catalysis has received growing interest due to the ubiquitous presence of this structural motif in numerous natural products, pharmaceuticals and functionalized materials. Employing this strategy, a wide variety of amides can be prepared effectively from halides, arenes and even alkanes under irradiation of visible light. These methods provide a robust alternative to well-established strategies for amide synthesis that involve condensation between a carboxylic acid and amine mediated by a stoichiometric activating agent. In this review, the representative progresses made on the synthesis of amides through visible light-mediated radical reactions are summarized. [ABSTRACT FROM AUTHOR]

Visible light photocatalytic radical carbonylation has been established as a robust tool for the efficient synthesis of carbonyl-containing compounds. Acyl radicals serve as the key intermediates in these useful transformations and can be generated from the addition of alkyl or aryl radicals to carbon monoxide (CO) or various acyl radical precursors such as aldehydes, carboxylic acids, anhydrides, acyl chlorides or α-keto acids. In this review, we aim to summarize the impact of visible light-induced acyl radical carbonylation reactions on the synthesis of oxygen and nitrogen heterocycles. The discussion is mainly categorized based on different types of acyl radical precursors. [ABSTRACT FROM AUTHOR]

The relationship between oxygen vacancy (OV) concentration of semiconductors and their photocatalytic performances is far from clarified. In this study, by tuning the OV concentration of BiOCl (001) surface via a novel H 2 O 2 treatment coupled infrared irradiation method, we demonstrate that OV concentration of BiOCl (001) surface strongly determine its surface atomic and electronic structures to modulate the photocatalytic pathways. Being of shorter Bi Bi and Bi O bond lengths as well as more electrons being less localized, BiOCl (001) surface with higher OV concentration favored molecular oxygen activation to generate O 2 2− via a two-electron transfer pathway, while the generated O 2 2− could prevent the over oxidation of amines and thus achieve high selectivity in the oxidation of amines to imines. Similar phenomena were also observed for other semiconductor photocatalysts such as TiO 2 and Nb 2 O 5 , suggesting the generality of oxygen vacancy concentration mediated selectivity enhancement. These findings shed light on the relationship between the oxygen vacancy concentration and the surface structure of semiconductor photocatalysts and offer a novel pathway to realize photocatalytic selective oxidation of amines to imines. [ABSTRACT FROM AUTHOR]

Review: [37 refs. [ABSTRACT FROM AUTHOR]

Review: 18 refs. [ABSTRACT FROM AUTHOR]

Review: 50 refs. [ABSTRACT FROM AUTHOR]

A novel [3 + 2] cycloaddition/oxidative aromatization sequence via visible light-induced photoredox catalysis is described. [ABSTRACT FROM AUTHOR]

An abstract of the article "De novo Synthesis of Imidazoles by Visible-Light-Induced Photocatalytic Aerobic Oxidation/[3 + 2] Cycloaddition/Aromatization Cascade" by Quiao-Hui Deng, You-Quan Zhou, Liang-Qui Lu, Zi-Long Tang, Jia-Rong Chen and Wen-Jing Xiao is presented.

The title synthesis provides an efficient access to highly functionalized pyrroles in good yields in the presence of organic dye photocatalyst. [ABSTRACT FROM AUTHOR]

The title reaction affords symmetrical and unsymmetrical 1,4-diketones which can be easily transformed into biologically valuable compounds [cf. [ABSTRACT FROM AUTHOR]

19 examples [ABSTRACT FROM AUTHOR]