Article
Chemistry, Organic
Zhi-Yong Ma, Mengyang Li, Li-Na Guo, Le Liu, Dongdong Wang, Xin-Hua Duan
Summary: The sulfonamide was investigated as a hydrogen-atom transfer catalyst for C(sp(3))-H alkylation based on DFT calculations, showing high regioselectivity and broad substrate scope. Additionally, the sulfonamide catalyst was also found to be applicable for C(sp(3))-C(sp(3) couplings through a combination of photoredox, nickel, and HAT catalysis.
Article
Chemistry, Multidisciplinary
Ting Wan, Zhenghui Wen, Gabriele Laudadio, Luca Capaldo, Rob Lammers, Juan A. Rincon, Pablo Garcia-Losada, Carlos Mateos, Michael O. Frederick, Remy Broersma, Timothy Noel
Summary: This study demonstrates the successful regioselective and scalable C(sp(3))-H amination via decatungstate photocatalysis using a newly developed high-intensity LED photoreactor. The platform enables fast results gathering and bridges the gap between academic discovery and industrial production.
ACS CENTRAL SCIENCE
(2022)
Article
Chemistry, Organic
Jing-Feng Zhao, Hua Wang, Hai-Bo Wang, Qin-Qin Tian, Yong-Qiang Zhang, Hai-Tao Feng, Wei He
Summary: A one-step protocol for desulfonylative allylation of C-H bonds using TBADT as a photo-hydrogen atom transfer catalyst is demonstrated. This method shows good functional group tolerance and can be applied for allylation of aldehydes and alkanes.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Pol Martinez-Balart, Balazs L. Toth, Alvaro Velasco-Rubio, Martin Fananas-Mastral
Summary: Here we report a photocatalytic methodology that enables the direct allylation of strong aliphatic C-H bonds with simple allylic chlorides. The method relies on the cooperative interaction of two metal catalysts, allowing for functionalization of a variety of chemical feedstocks and natural products under mild conditions in short reaction times.
Article
Chemistry, Multidisciplinary
Nobukazu Taniguchi, Mamoru Hyodo, Lin-Wei Pan, Ilhyong Ryu
Summary: Site-selective C(sp(3))-H thiolation has been achieved using thiosulfonates as substrates and the decatungstate anion as a photocatalyst. The reaction proceeds through a cascade of double S(H)2 reactions, HAT and ArS group transfer, and PCET, allowing the recovery of the catalyst, W10O324-.
CHEMICAL COMMUNICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Zheliang Yuan, Robert Britton
Summary: Photocatalytic C-H functionalization reactions have gained increasing attention for their mild reaction conditions and complementary selectivities. This perspective focuses on the development of a photocatalytic decatungstate catalyzed C-H fluorination reaction and its practical applications, as well as the exploration of decatungstate for C-H fluoroalkylation and the electrostatic effects observed in decatungstate-catalyzed C-H functionalization. It aims to inspire further research in the use of decatungstate and the exploitation of electrostatic effects in these reactions.
Article
Chemistry, Physical
Fatma Feyza Ozgen, Alexandra Jorea, Luca Capaldo, Robert Kourist, Davide Ravelli, Sandy Schmidt
Summary: The combination of photocatalysis and biocatalysis enables the direct conversion of simple aldehydes and acrylates into chiral gamma-lactones. This synthesis method provides a highly selective and efficient approach to access high-value added chiral compounds.
Article
Chemistry, Multidisciplinary
Rui Wang, Chuan Wang
Summary: By combining nickel-mediated aza-Heck cyclization and radical acyl C-H activation, a highly enantioselective imino-acylation of oxime ester-tethered alkenes with aldehydes was achieved using tetrabutylammonium decatungstate (TBADT) as a hydrogen atom transfer (HAT) photocatalyst. The reaction provides a convenient route to synthesize enantioenriched pyrrolines bearing an acyl-substituted stereogenic center under mild conditions. Preliminary mechanistic studies indicate a Ni(i)/Ni(ii)/Ni(iii) catalytic sequence involving intramolecular migratory insertion of a tethered olefin into the Ni(iii)-N bond as the enantiodiscriminating step.
Article
Chemistry, Physical
Charles B. Musgrave, Kaeleigh Olsen, Nichole S. Liebov, John T. Groves, William A. Goddard, T. Brent Gunnoe
Summary: The decatungstate anion (DT) is a useful photocatalyst for C-H functionalization in organic transformations. We demonstrate the photochemical partial oxidation of methane to methyl trifluoroacetate using DT as a catalyst. The proposed mechanism involves synergistic relationships among DT, chloride, and iodine species to achieve efficient aerobic methane partial oxidation.
Article
Chemistry, Organic
Vetrivelan Murugesan, Anirban Ganguly, Ardra Karthika, Ramesh Rasappan
Summary: The site-selective C-H functionalization using the dual Ni/photoredox system has been successfully employed for generating acyl radicals from aldehydes to produce ketones. Furthermore, a new cross-coupling reaction via C-N bond cleavage using nickel and TBADT catalyst has been developed, providing a broad spectrum of functional group-tolerant ketones.
Article
Chemistry, Organic
Masahiro Ueda, Atsuki Kitano, Hiroshi Matsubara
Summary: The selective hydrogen abstraction reactions on sp(3) carbons with oxyradicals were investigated using ab initio and DFT calculations. It was found that beta-hydrogen abstraction was favorable, consistent with experimental findings. NBO analysis revealed that the transferred hydrogen atom is partially positively charged when abstracted by an oxyradical, and hydrogens bonded to the most positively charged carbon in the substrate were predominantly abstracted, providing a simple compass for predicting regioselectivity in the functionalization of C(sp(3))-H bonds with oxyradicals.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Chifeng Li, Chen Gu, Kazuya Yamaguchi, Kosuke Suzuki
Summary: Photocatalytic polymer degradation is a promising solution to global plastic waste disposal. In this study, it was demonstrated that various polyesters and polyethers can be efficiently degraded in the presence of a polyoxometalate photocatalyst, specifically decatungstate (W10). The degradation efficiency of W10 was notably higher than previously reported photocatalysts.
Article
Chemistry, Multidisciplinary
Punith S. Gowda, Duddu S. Sharada, Gedu Satyanarayana
Summary: This work presents a method for constructing dihydrobenzofuran (DHB) scaffolds through a photoinduced visible light-mediated radical cyclization. The cascade photochemical process is compatible with various aromatic aldehydes and diverse alkynyl aryl ethers, and proceeds via an intramolecular 1,5-hydrogen atom transfer (HAT) pathway. Importantly, acyl C-H activation under mild conditions is achieved without the use of additives or reagents. The photocatalyst, tetrabutylammonium decatungstate (TBADT), plays a crucial role by facilitating the well-known hydrogen atom transfer during the reaction.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Applied
Yi-Ting Wang, Yi-Lun Shih, Yen-Ku Wu, Ilhyong Ryu
Summary: Site-selective C(sp(3))-H alkenylation was achieved under photo-irradiation in the presence of a catalytic decatungstate anion. The reaction successfully combines radical addition/beta-scission sequence with photocatalytic C(sp(3))-H functionalization. The decatungstate anion participates in a chain-repairing step in reactions with weaker C-H bonds.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Lipeng Qiao, Xiaoyang Fu, Yafeng Si, Xiaolan Chen, Lingbo Qu, Bing Yu
Summary: A photocatalytic strategy using tetrabutylammonium decatungstate (TBADT) as a hydrogen atom transfer (HAT) photocatalyst and aldehydes as radical precursors was developed for the controllable aroylation or diaroylation of allyl sulfones. By adjusting the substrate ratio, the selectivity of the reaction could be easily tuned, resulting in the installation of various aroyl groups on allyl sulfones, and the formation of beta,gamma-unsaturated ketones and 1,5-diketones with moderate to excellent yields. This methodology offers mild conditions, high step economy, no external additive, readily available resources, and broad substrate scope.
Article
Chemistry, Multidisciplinary
Zafar Mahmood, Jia He, Shuqing Cai, Zhanxiang Yuan, Hui Liang, Qian Chen, Yanping Huo, Burkhard Koenig, Shaomin Ji
Summary: This study demonstrates the tuning of the redox potential and excited state properties of a commercially available photocatalyst for the visible-light-mediated photoredox phosphorylation of tertiary aliphatic amines. It also showcases the successful synthesis of alpha-aminophosphinoxides and alpha-aminophosphonates through cross-dehydrogenative coupling reactions using Ru-II complexes as photocatalysts.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Applied
Ritu, Daniel Kolb, Nidhi Jain, Burkhard Koenig
Summary: Several methods for the direct desaturation of aliphatic compounds have been developed using photoredox and transition-metal catalysis, allowing for the straightforward preparation of highly functionalized alkenes.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Ya-Ming Tian, Evamaria Hofmann, Wagner Silva, Xiang Pu, Didier Touraud, Ruth M. M. Gschwind, Werner Kunz, Burkhard Koenig
Summary: The amino alcohol meglumine solubilizes organic compounds in water and enforces the formation of electron donor acceptor (EDA) complexes, resulting in unique cross-coupling reactions. UV-A photoinduced electron transfer within the EDA complexes leads to the cleavage of halide ions and recombination of arenes, followed by rearomatization and proton loss. UV and NMR measurements demonstrate the significance of the EDA aggregates for the photoinduced reaction. Enforced EDA aggregate formation in water provides new activation modes for organic photochemical synthesis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Michela Marcon, Stefano Crespi, Andreas Pielmeier, Burkhard Koenig
Summary: This study presents the first photoswitchable copper complex with catechol oxidase activity. The Z-configuration, which optimizes the distance between the two copper centers, is found to enhance the catalytic activity for catechol oxidation compared to the E-configuration.
CHEMICAL COMMUNICATIONS
(2023)
Article
Electrochemistry
Tobias A. Karl, Max Seidl, Burkhard Koenig
Summary: An induction-based energy harvesting device was developed to convert rotational energy into electrical energy for electrochemical transformations. The device can provide adjustable voltage by adjusting the stirring rate of the reaction. Experimental results showed the comparability of the device with commercial power supplies in various late-stage functionalization reactions, making it a cost-effective alternative for electrochemical reactions in laboratories without specialized equipment.
Article
Chemistry, Multidisciplinary
Ulrike Wirth, Julia Erl, Saphia Azzam, Carina Hoering, Michael Skiba, Ritu Singh, Kathrin Hochmuth, Max Keller, Joachim Wegener, Burkhard Koenig
Summary: Combining photochromic NPY receptor ligands with label-free impedance assays allows observing the cell response to receptor activation and its reversibility over time.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Alessa B. Rolka, Nataliya Archipowa, Roger J. Kutta, Burkhard Koenig, F. Dean Toste
Summary: This article presents the syntheses of two novel, organic, and chiral photocatalysts. By combining donor-acceptor cyanoarene-based photocatalysts with a chiral phosphoric acid, bifunctional catalysts have been designed. Their application in both enantioselective energy transfer and photoredox catalysis is demonstrated in preliminary proof-of-concept reactions.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Multidisciplinary Sciences
Indrajit Ghosh, Nikita Shlapakov, Tobias A. Karl, Jonas Dueker, Maksim Nikitin, Julia V. Burykina, Valentine P. Ananikov, Burkhard Koenig
Summary: Adaptive dynamic homogeneous catalysis (AD-HoC) with nickel under visible-light-driven redox reaction conditions allows for general C(sp(2))-(hetero)atom coupling reactions with various nucleophiles. The self-adjustive nature of the catalytic system simplifies the classification and optimization process, resulting in predictable reaction conditions and hundreds of synthetic examples.
Article
Chemistry, Multidisciplinary
Pascal Puellmann, Dominik Homann, Tobias A. Karl, Burkhard Koenig, Martin J. Weissenborn
Summary: Fungal unspecific peroxygenases (UPOs) have attracted attention as versatile oxyfunctionalization catalysts with impressive catalytic capabilities. However, their sensitivity towards co-substrate hydrogen peroxide poses a challenge. This study introduces the concept of light-dependent UPO biocatalysis with genetically encoded flavin-containing photosensitizer proteins for in situ hydrogen peroxide production, enabling efficient catalysis setups and the extraction of enantiomerically pure alcohol products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Evamaria Hofmann, Pierre Degot, Didier Touraud, Burkhard Koenig, Werner Kunz
Summary: The demand for natural vanilla extract, specifically vanillin, is much higher than current production due to the labor-intensive process of vanilla bean cultivation and vanillin extraction. To meet this demand, most vanillin used today is synthetically produced, contrary to the trend towards bio-based products. This study focuses on synthesizing nature-based vanillin from the more accessible rhizomes of Curcuma longa, which also produces vanillic acid and p-hydroxybenzaldehyde found in natural vanilla beans. Visible light and food-grade chemicals are utilized for the extraction and conversion of curcuminoids to flavors. The use of a binary mixture of ethanol and triacetin, as well as a surfactant-free microemulsion consisting of water, ethanol, and triacetin, achieves extraction results exceeding those reported in the literature for Soxhlet extraction of vanilla beans by a factor of more than 7.
Article
Chemistry, Medicinal
Ulrike Wirth, Konstantin Raabe, Predrag Kalaba, Erik Keimpema, Markus Muttenthaler, Burkhard Koenig
Summary: In this study, 12 photoprobes derived from oxytocin and vasopressin were designed, synthesized, and characterized for their (photo)pharmacological properties. Two photoprobes with good potency and photoswitch window for investigating OTR and V1bR were identified, showing their potential value in studying receptor activation processes in specific regions of the brain.
JOURNAL OF MEDICINAL CHEMISTRY
(2023)
Article
Chemistry, Organic
Nabakumar Bera, Bhabani Sankar Lenka, Burkhard Konig, Debayan Sarkar
Summary: Dearomative spiro-etherification of naphthols was achieved using catalytic amounts of riboflavin tetracetate (RFTA) as a photosensitizer and molecular oxygen as a terminal oxidizing agent under blue light (440 nm) irradiation in the presence of acid. The presence of acid increased the photooxidation power of RFTA and facilitated the dearomatization reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Vincent George, Burkhard Koenig
Summary: Prompted by the increasing interest in strained hydrocarbons as potential drug candidates, the researchers developed a simple and efficient photochemical protocol for the synthesis of (spiro)cyclopropanes from stable tosylhydrazones and electron-poor olefins. This protocol involves a two-step one-pot transformation using donor-donor diazo compounds and subsequent nitrogen extrusion of the intermediate UΔ1-pyrazoline. Notably, kinetic analysis allowed for the isolation of intermediate spiro-heterocycles.
CHEMICAL COMMUNICATIONS
(2023)
