Article
Chemistry, Organic
Jazmin Garcia-Ramirez, Luis A. Gonzalez-Cortes, Luis D. Miranda
Summary: A short strategy involving radical addition/cyclization cascade reaction and Pd-mediated cyclization was employed to synthesize three representative alkaloids of the (+/-)-rhazinilam family and 10 non-natural analogs.
Article
Chemistry, Organic
Kensuke Kiyokawa, Ikumi Noguchi, Takaya Nagata, Satoshi Minakata
Summary: In this study, we demonstrate the bromocyanation of styrene derivatives with cyanogen bromide using tris(pentafluorophenyl)borane as a Lewis acid catalyst. This protocol enables a stereospecific syn-addition and provides an accessible route to beta-bromonitriles.
Article
Chemistry, Organic
Kensuke Kiyokawa, Ikumi Noguchi, Takaya Nagata, Satoshi Minakata
Summary: In this study, we present a bromocyanation reaction of styrene derivatives using cyanogen bromide in the presence of tris(pentafluorophenyl)borane as a Lewis acid catalyst. The reaction proceeds through a stereospecific syn-addition and provides a straightforward approach to beta-bromonitriles.
Article
Chemistry, Physical
Patricia C. Lin, Chetan Joshi, Tristan M. McGinnis, Sharath Chandra Mallojjala, Amberly B. Sanford, Jennifer S. Hirschi, Elizabeth R. Jarvo
Summary: A nickel-catalyzed cross-electrophile coupling reaction was developed for the synthesis of enantioenriched cyclopropane products containing vinyl fluoride substituents. The reaction involves the C-F bond activation of allylic gem-difluorides or the C-O bond activation of unactivated alkyl sulfonates. The findings of this study have significant implications in medicinal chemistry.
Article
Chemistry, Physical
Chang-Sheng Wang, Yongqi Yu, Yusuke Sunada, Chen Wang, Naohiko Yoshikai
Summary: This article reports a cobalt-catalyzed carbo- and hydrocyanation reaction of alkynes, which involves C-CN bond cleavage of organic cyanides. A low-valent cobalt-diphosphine catalyst, generated by reduction with Zn, is used to promote the arylcyanation of alkynes with trans-selectivity. Additionally, the addition of Zn(OTf)2 to the catalytic system accelerates the reaction and switches the stereoselectivity.
Article
Chemistry, Physical
Adam Cook, Haydn MacLean, Piers St Onge, Stephen G. Newman
Summary: A catalytic method for direct deoxygenation of various C-O bond-containing functional groups is reported. The reaction, using a Ni(II) pre-catalyst and silane reducing agent, selectively reduces alcohols, epoxides, ethers, aldehydes, and ketones to their corresponding alkanes while leaving other functional groups untouched. Practical applications in catalytic deuteration, benzyl ether deprotection, and valorization of biomass-derived feedstocks demonstrate the versatility of this methodology.
Article
Chemistry, Applied
Ke Wu, Qiang Rong, Nan Sun, Baoxiang Hu, Zhenlu Shen, Liqun Jin, Xinquan Hu
Summary: A new nickel-catalyzed amination method has been developed for the synthesis of diarylamines through C-CN bond activation of aryl nitriles with anilines. Various aromatic and heteroaromatic nitriles were used as electrophiles to couple with substituted anilines, resulting in a diverse range of diarylamines with yields ranging from 15% to 95%.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Alexander Friedrich, Jonathan Eyselein, Jens Langer, Christian Faerber, Sjoerd Harder
Summary: Experimental and computational studies show that the metal-metal bonds to zinc are more covalent, whereas those to magnesium are described as weak Al-I(or Ga-I)-> Mg2+ donor bonds. Additionally, failure to isolate the zinc-aluminum combination is attributed to cleavage of the C-F bond in the solvent fluorobenzene.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Gilles De Smet, Xingfeng Bai, Carl Mensch, Sergey Sergeyev, Gwilherm Evano, Bert U. W. Maes
Summary: This study demonstrates that acetate can serve as a renewable leaving group for selective deoxygenation of phenolics. The Ni-catalyzed reaction in a green solvent allows for efficient deoxygenation without affecting specific functional groups.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Yun-Cheng Luo, Ming-Kuan Wang, Ling-Chao Yu, Xingang Zhang
Summary: Here, we report a nickel-catalyzed selective C(sp(2))-F bond alkylation of HFO-1234yf with alkylzinc reagents, resulting in 2-trifluoromethylalkenes that can serve as versatile synthons for diversified transformations. Mechanistic studies reveal that the addition of lithium salt is crucial for promoting the oxidative addition of Ni-0(L-n) to the C-F bond, and less electron-rich N-based ligands exhibit comparable or higher oxidative addition rates compared to electron-rich phosphine ligands.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Zhouen Zhang, Takashi Niwa, Kenji Watanabe, Takamitsu Hosoya
Summary: In this study, a two-phase radiosynthetic method for the ipso-C-11-cyanation of aryl fluorides was developed, using nickel-mediated C-F bond activation. A practical protocol was established that does not require a glovebox, making it applicable for general PET centers. This method enabled the efficient synthesis of diverse [C-11]aryl nitriles, including pharmaceutical drugs. Stoichiometric reactions and theoretical studies demonstrated the significant promotion effect of lithium chloride on the oxidative addition, facilitating rapid C-11-cyanation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Tingting Sun, Jintong Zhang, Yijun Fang, Yu Zhou, Haiqun Cao, Gen Luo, Zhi-Chao Cao
Summary: Despite the challenge in selectively substituting an unactivated C-O bond, this study achieved enantioselective alkylative activation using a chiral nickel catalyst. The use of THF as a solvent facilitated the transformation by suppressing beta-H elimination. DFT calculations revealed the crucial role of THF coordination to Mg(II) in preventing beta-H elimination during reductive elimination.
Article
Chemistry, Physical
Qing Wang, Kang-Bao Zhong, Hao Xu, Shi-Nan Li, Wei-Ke Zhu, Fei Ye, Zheng Xu, Yu Lan, Li-Wen Xu
Summary: Transition-metal-catalyzed silicon-carbon bond activation is an important process in organosilicon chemistry and homogeneous catalysis. This study reports a convenient and enantioselective Si-C bond cleavage-initiated [4 + 2] annulation, providing access to chiral six-membered oxasilacycles and their derivatives with high yields and enantioselectivities.
Article
Chemistry, Multidisciplinary
Arne Merschel, Timo Glodde, Beate Neumann, Hans-Georg Stammler, Rajendra S. Ghadwal
Summary: This study reports the intramolecular 1,2-Dipp migration of seven mesoionic carbenes under nickel catalysis to generate 1,3-imidazoles. The use of these compounds to access super-iMICs demonstrates their superior stereoelectronic properties. The results reveal unprecedented reaction pathways in NHC chemistry.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Haruka Kawakam, Naoto Chatan
Summary: The reaction between N-pyrimidinyl aniline derivatives and internal alkynes in the presence of a catalytic amount of Ni(0) complex leads to the alkyne annulation of C-F/N-H, resulting in the formation of indole derivatives. The activation of the C-F bond, a crucial step in this reaction, is facilitated by a pyrimidine directing group. The use of a base, such as NaH, is necessary for the completion of the reaction.
Review
Chemistry, Multidisciplinary
Yoshiaki Nakao
Summary: Nitriles are versatile building blocks in organic synthesis, with common reactions including transformations of cyano groups. While the C-CN bond of nitriles is thermodynamically robust and rarely used as a reaction site, metal-catalyzed reactions have shown the potential for activation. These reactions are categorized into those using CN as a leaving group and those utilizing nitriles as a source of CN groups, offering new possibilities for organic synthesis.
Article
Chemistry, Multidisciplinary
Kazuhiko Semba, Naoki Ohta, Fritz Paulus, Masaki Ohata, Yoshiaki Nakao
Summary: This new method allows for allylarylation of electron-deficient alkenes using aryl boronates and allylic carbonates as starting materials, leading to a variety of carbon skeletons. Mechanistic studies reveal that the reaction is facilitated by a cooperative catalysis involving Pd-0/Pd-II redox and Pd-II/Pd-II non-redox catalytic cycles.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Naofumi Hara, Konosuke Yamamoto, Yuuki Tanaka, Teruhiko Saito, Shigeyoshi Sakaki, Yoshiaki Nakao
Summary: In this study, rhodium complexes with X-type PBP and PGaP pincer ligands were synthesized, showing that the sigma-donicity and trans-influence of the X-type boryl ligand are stronger than those of the X-type gallyl ligand. The Lewis acidity of the PEP-Rh complexes (E = B, Al, Ga) was examined, with experimental and computational results indicating that the Lewis acidity increases in the order B (1) < Ga < Al.
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN
(2021)
Article
Chemistry, Multidisciplinary
Rin Seki, Naofumi Hara, Teruhiko Saito, Yoshiaki Nakao
Summary: In this study, we reported a novel rhodium catalyst with X-type PAlP pincer ligand for catalytic reduction of a C-O bond and borylation. The reaction mechanism was revealed through characterization of reaction intermediate and deuterium-labeling experiments. This catalytic system demonstrated steric-hindrance-dependent chemoselectivity, providing a new strategy for selective C-O bond activation through heterobimetallic catalysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Kazuhiko Semba, Yasuhiro Ohtagaki, Yoshiaki Nakao
Summary: A method for 1,2-arylboration of aliphatic alkenes to afford alkylboronic esters through cooperative palladium/copper catalysis was developed, showing high regioselectivity and tolerance to various functional groups under the reaction conditions.
TETRAHEDRON LETTERS
(2021)
Review
Chemistry, Multidisciplinary
Myuto Kashihara, Yoshiaki Nakao
Summary: Cross-coupling reactions using nitroarenes as electrophiles have gained attention due to their ease of accessibility and potential advantages over haloarenes. Recent research has focused on developing new catalyst systems and reaction conditions to improve the efficiency and practicality of these reactions, with promising results in diversifying bond-forming reactions and reducing catalyst loading. Research in this field is expected to continue growing as the utility of nitroarenes in organic synthesis is reevaluated.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Inorganic & Nuclear
Naoki Matsushita, Myuto Kashihara, Michele Formica, Yoshiaki Nakao
Summary: Through the use of a new designed ligand, Pd-catalyzed etherification of nitroarenes with arenols was achieved, allowing for the direct access to a range of unsymmetrical diaryl ethers. The design of the ligand facilitated both the oxidative addition and reductive elimination steps of the catalytic cycle, providing mechanistic insights for optimizing the reaction.
Article
Chemistry, Organic
Naofumi Hara, Koki Aso, Qiao-Zhi Li, Shigeyoshi Sakaki, Yoshiaki Nakao
Summary: This study reports a C2-and mono-selective alkylation of various pyridines and azines with unactivated alkenes and vinylarenes using a heterobimetallic Rh-Al catalyst. Experimental results show that the use of aliphatic alkenes exclusively affords linear alkylation products, while vinylarenes mainly afford branched alkylation products. The details of the reaction mechanism, revealed by DFT calculations, indicate that the reductive elimination of the products is rate-determining, consistent with experimental results. The origin of the linear/branched selectivity is elucidated based on deformation/interaction analysis.
Article
Chemistry, Applied
Qiao-Zhi Li, Naofumi Hara, Kazuhiko Semba, Yoshiaki Nakao, Shigeyoshi Sakaki
Summary: Rh(PAlP) is a new type of catalyst for reactions via sigma-bond activation, showing unique Rh-Al direct bond, flexible substrate coordination, and new catalytic functions for C-H and C-F sigma-bond activations. The unusual Rh delta--Al delta+ polarization and coordination flexibility play important roles in these catalytic reactions.
TOPICS IN CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Kazuhiko Semba, Fumiya Shimoura, Yoshiaki Nakao
Summary: A cobalt complex ligated with a PAlP pincer ligand was synthesized and the Lewis acidity of the aluminum atom on the cobalt complex was confirmed by coordination with 4-dimethylaminopyridine (DMAP). Reactions of the cobalt complex with H2O, EtOH, i-PrOH, and t-BuOH efficiently yielded the corresponding cobalt hydride complexes.
Article
Chemistry, Physical
Naofumi Hara, Kazuhiko Semba, Yoshiaki Nakao
Summary: Transition metal complexes with X-type aluminyl ligands exhibit strong reactivity and enable various challenging catalytic transformations such as transfer dehydrogenation, highly efficient CO2 reduction, and site-selective C-H bond functionalization.
Article
Chemistry, Organic
Ikuya Fujii, Kazuhiko Semba, Yoshiaki Nakao
Summary: Rhodium-aluminum bimetallic complexes catalyze the Kumada-Tamao-Corriu (KTC) cross-coupling reaction using arylmagnesium compounds generated from corresponding aryl fluorides or chlorides. This method allows the challenging KTC coupling reaction to be carried out using aryl fluorides as nucleophiles, resulting in various biaryls.
Review
Chemistry, Organic
Yoshiaki Nakao
Summary: C-H functionalization is a key technique in organic synthesis to simplify chemical processes by converting unfunctionalized C-H bonds into functional groups. Traditionally, functionalization required pre-functionalized compounds, but now direct transformation is possible. However, current strategies using directing groups and additional steps limit efficiency, while a new approach utilizing Lewis acid-base formations to control site-selectivity of functionalization is being explored.
JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN
(2021)
Article
Chemistry, Multidisciplinary
Naofumi Hara, Nao Uemura, Yoshiaki Nakao
Summary: A C2-selective mono-silylation of various pyridines has been developed using a Rh-Al complex, where the site- and mono-selectivity are controlled by the coordination of pyridine to the Lewis-acidic Al center. A reaction mechanism is proposed based on the isolation of a (2-pyridyl)silylrhodium intermediate from several mechanistic studies.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Kitty K. Asahara, Myuto Kashihara, Kei Muto, Yoshiaki Nakao, Junichiro Yamaguchi
Summary: The activation of Ar-NO2 bonds by Pd/BrettPhos catalyst has enabled denitrative couplings, overcoming the bottleneck of general denitrative transformations. Deep understanding of the reaction mechanism also led to the design of a more active Pd/NHC system.
JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN
(2021)
Article
Chemistry, Organic
Fuying Zhu, Yamei Lin
Summary: In this study, a low-metal iron-supported catalyst (Fe20/NC-Mg) was reported for the efficient synthesis of quinoxaline compounds, using water as a solvent and without additional bases. The synergistic effect of FeNx site and Mg (OH)2 nanorods in the catalyst played a key role in achieving high yields (82-91%) in 16 examples. The gram-level synthesis and reusability of the catalysts after four cycles demonstrated its industrial application potential.
Article
Chemistry, Organic
Mikhail Kozlov, Alexey Tyurin, Andrey Dmitrenok, Vyacheslav Rusak, Aleksander Fedorov, Igor Zavarzin, Yulia Volkova
Summary: This study presents a novel and practical synthesis method for phosphorus-substituted 1,3,4-thiadiazolines using phosphorylthioformic acid hydrazides and ketones. The protocol demonstrates operational simplicity, availability of reagents, and tolerance towards different functional groups.
Article
Chemistry, Organic
Jisna Jose, Thomas Mathew
Summary: 2-Cyclopentenone and its derivatives are highly esteemed synthetic intermediates with exceptional utility in organic synthesis. They are favored structural motifs in numerous pharmaceutical drugs and natural products, highlighting their significance. The review discusses the various methods used to synthesize cyclopentenones from 2016 to 2023.