114180-12-0Relevant articles and documents
Photocycloaddition of Cinnamates in Flow and Development of a Thiourea Catalyst
Telmesani, Reem,Park, Sung H.,Lynch-Colameta, Tessa,Beeler
, p. 11521 - 11525 (2015)
Cyclobutanes derived from the dimerization of cinnamic acids are the core scaffolds of many molecules with potentially interesting biological activities. By utilizing a powerful flow photochemistry platform developed in our laboratory, we have evaluated t
Heteroleptic copper(I) complexes as energy transfer photocatalysts for the intermolecular [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides
Wu, Qing-An,Ren, Chen-Chao,Chen, Feng,Wang, Tian-Qi,Zhang, Yu,Liu, Xue-Fen,Chen, Jian-Bin,Luo, Shu-Ping
supporting information, (2021/05/10)
The [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides can be effectively catalyzed by heteroleptic copper(I) complexes. The reactions were carried out under mild reaction conditions and the products were obtained in 20–72% yield under visible light irradiation. The copper-based photocatalyst comprised of the rigid phenanthroline ligand with substituents at the 2,9-positions and the 4,7-positions showed high activity in the photodimerization via an energy transfer pathway.
Photocatalytic Oxidative [2+2] Cycloelimination Reactions with Flavinium Salts: Mechanistic Study and Influence of the Catalyst Structure
Hartman, Tomá?,Reisnerová, Martina,Chudoba, Josef,Svobodová, Eva,Archipowa, Nataliya,Kutta, Roger Jan,Cibulka, Radek
, p. 373 - 386 (2021/02/01)
Flavinium salts are frequently used in organocatalysis but their application in photoredox catalysis has not been systematically investigated to date. We synthesized a series of 5-ethyl-1,3-dimethylalloxazinium salts with different substituents in the positions 7 and 8 and investigated their application in light-dependent oxidative cycloelimination of cyclobutanes. Detailed mechanistic investigations with a coumarin dimer as a model substrate reveal that the reaction preferentially occurs via the triplet-born radical pair after electron transfer from the substrate to the triplet state of an alloxazinium salt. The very photostable 7,8-dimethoxy derivative is a superior catalyst with a sufficiently high oxidation power (E=2.26 V) allowing the conversion of various cyclobutanes (with Eox up to 2.05 V) in high yields. Even compounds such as all-trans dimethyl 3,4-bis(4-methoxyphenyl)cyclobutane-1,2-dicarboxylate can be converted, whose opening requires a high activation energy due to a missing pre-activation caused by bulky adjacent substituents in cis-position.
Donor-acceptor fluorophores as efficient energy transfer photocatalysts for [2 + 2] photodimerization
Chen, Feng,Chen, Hao,Liu, Xue-Fen,Luo, Shu-Ping,Ren, Chen-Chao,Wu, Qing-An,Xu, Liang-Xuan,Yu, Xiao-Cong
supporting information, p. 3707 - 3716 (2020/06/03)
Mild [2 + 2] photodimerization of enone substrates was induced by donor-acceptor fluorophores. Enone substrates were activated efficiently for anti-head to head dimerizations with a high yield (up to 83%) and high selectivity. The adjustable excited state potential also allows donor-acceptor fluorophores to be used for isomerization of the above substrates, confirming the potential of donor-acceptor fluorophores as energy transfer photocatalysts.
Hydrogen Atom Transfer Reactions via Photoredox Catalyzed Chlorine Atom Generation
Rohe, Samantha,Morris, Avery O.,McCallum, Terry,Barriault, Louis
supporting information, p. 15664 - 15669 (2018/10/26)
The selective functionalization of chemically inert C?H bonds remains to be fully realized in achieving organic transformations that are redox-neutral, waste-limiting, and atom-economical. The catalytic generation of chlorine atoms from chloride ions is one of the most challenging redox processes, where the requirement of harsh and oxidizing reaction conditions renders it seldom utilized in synthetic applications. We report the mild, controlled, and catalytic generation of chlorine atoms as a new opportunity for access to a wide variety of hydrogen atom transfer (HAT) reactions owing to the high stability of HCl. The discovery of the photoredox mediated generation of chlorine atoms with Ir-based polypyridyl complex, [Ir(dF(CF3)ppy)2(dtbbpy)]Cl, under blue LED irradiation is reported.
Method for constructing four-membered ring through visible light catalytic [2+2] reaction
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Paragraph 0199-0201, (2018/11/03)
The invention discloses a method for constructing a four-membered ring through visible light catalytic [2+2] reaction. The method comprises the following steps: 1.1) adding an unsaturated double-bondcompound and a photosensitizer into a solvent to obtain a solution A; 1.2) irradiating the solution A by using visible light under the argon atmosphere to obtain a dimerized[2+2]cyclobutane product; or 2.1) adding the unsaturated double-bond compound, a styrene compound and the photosensitizer into a solvent to obtain a solution B; and 2.2) irradiating the solution B by using visible light under the argon environment to obtain a crossed [2+2]cyclobutane product. The visible light sensitizer is utilized for the first time and non-rigid double-bond intermolecular[2+2]cyclization reaction is realized; the use amount of the light sensitizer is small, the reaction can be realized under the argon environment by utilizing the visible light or sunlight, and the reaction condition is mild; and thewhole process is simple and efficient, and potential application in organic reaction and industrial production is embodied.
Photosensitised regioselective [2+2]-cycloaddition of cinnamates and related alkenes
Pagire, Santosh K.,Hossain, Asik,Traub, Lukas,Kerres, Sabine,Reiser, Oliver
supporting information, p. 12072 - 12075 (2017/11/14)
An efficient method for the synthesis of substituted cyclobutanes from cinnamates, chalcones, and styrenes has been developed utilizing a visible-light triplet sensitisation mode. This reaction provides a diverse range of substituted cyclobutanes in high yields under mild conditions without the need of external additives. Good regioselectivity is obtained due to strong π-π-stacking of arene moieties, whereas diastereoselectivity relies on the electronic effects or ortho-substitution of the arene substrate. The utility of this transformation is demonstrated by the formal synthesis of the lignane natural product (±)-Tanegool.
General and Efficient Intermolecular [2+2] Photodimerization of Chalcones and Cinnamic Acid Derivatives in Solution through Visible-Light Catalysis
Lei, Tao,Zhou, Chao,Huang, Mao-Yong,Zhao, Lei-Min,Yang, Bing,Ye, Chen,Xiao, Hongyan,Meng, Qing-Yuan,Ramamurthy, Vaidhyanathan,Tung, Chen-Ho,Wu, Li-Zhu
supporting information, p. 15407 - 15410 (2017/11/13)
[2+2] Photocycloaddition, for example, the dimerization of chalcones and cinnamic acid derivatives, is a unique strategy to construct cyclobutanes, which are building blocks for a variety of biologically active molecules and natural products. However, most attempts at the above [2+2] addition have focused on solid-state, molten-state, or host–guest systems under ultraviolet-light irradiation in order to overcome the competition of facile geometric isomerization of nonrigid olefins. We report a general and simple method to realize the intermolecular [2+2] dimerization reaction of these acyclic olefins to construct cyclobutanes in a highly regio- and diastereoselective manner in solution under visible light, which provides an efficient solution to a long-standing problem.
Exploitation of sugar ring flipping for a hinge-type tether assisting a [2 + 2] cycloaddition
Yuasa, Hideya,Nakatani, Masatoshi,Hashimoto, Hironobu
, p. 3694 - 3702 (2008/10/09)
Methyl 3-O-p-methoxybenzyl-β-d-xylopyranoside (2) was exploited as a novel hinge-type tether for the [2 + 2] cycloaddition of cinnamate. The major ring conformation occupied by the 2,4-dicinnamate derivative of 2 was 4C1, which exten
Controlled photocycloaddition of unsaturated carboxylates intercalated in hydrotalcite clay interlayers
Takagi, Katsuhiko,Shichi, Tetsuya,Usami, Hisanao,Sawaki, Yasuhiko
, p. 4339 - 4344 (2007/10/02)
Photochemical cycloaddition for several unsaturated carboxylates has been studied in the presence of hydrotalcite clays. Syn head-to-head cyclodimers were selectively formed in the irradiation of sodium cinnamates intercalated in the dispersed clays. On the other hand, two isomers of syn head-to-head and syn head-to-tail cyclodimers were formed for the case of (phenylethenyl)benzoates. The degree of intercalation was shown to be dependent on the structures of the carboxylates. X-ray diffraction analyses revealed that the carboxylates are intercalated as a monolayer, which suggests an alternate anti-parallel packing since a clay interlayer possesses two ionic surfaces, top and bottom. The product selectivity was shown to be controlled by the relative distances of double bonds from the ionic surfaces of the clay. The molecular aggregates of intercalated carboxylates were affected by adding photoinactive coadsorbates; the major photochemical processes shifted from photocycloadditions to cis-trans isomerizations and from excimer to monomer fluorescence emissions.
