Article
Chemistry, Multidisciplinary
Rupkumar Khuntia, Sanat Kumar Mahapatra, Lisa Roy, Subhas Chandra Pan
Summary: In this study, a new method has been developed to rapidly synthesize structurally diverse and complex molecules from easily available starting materials through catalytic reactions. Through the analysis of the mechanistic intricacies, the roles of chiral and Lewis base catalysts in the reaction have been investigated.
Article
Chemistry, Multidisciplinary
Rupkumar Khuntia, Sanat Kumar Mahapatra, Lisa Roy, Subhas Chandra Pan
Summary: An important goal in organic synthesis and medicinal chemistry is to efficiently and affordably synthesize structurally diverse and complex molecules from readily available starting materials. In this study, a protocol for the synthesis of benzofuran fused azocine derivatives and spiro-cyclopentanone benzofurans has been developed. The method involves sequential catalysis with chiral H-bonding catalyst and Lewis base catalyst. The products exhibit high yields and high stereo- and enantioselectivities.
Article
Chemistry, Organic
Jian-Xiang Zhu, Fu Pi, Teng Sun, Wen-Yu Huang, Lu Gao, Zhi-Chao Chen, Wei Du, Ying-Chun Chen
Summary: This article introduces a palladium-catalyzed tandem reaction that proceeds through sequential 2,4-dienylation/Michael addition/pi-sigma-pi isomerization/allylic alkylation. Using ortho-functionalized aryl enones and 2,4-dienyl carbonates as substrates, enantioenriched architectures with fused and spirocyclic frameworks are constructed in moderate to excellent yields and stereoselectivity. Importantly, the intrinsic intramolecular Diels-Alder reaction pattern of the dienylated intermediates is effectively reversed via Pd(0)-pi-Lewis base catalysis.
Article
Chemistry, Multidisciplinary
Md Firoj Hossain, Subrata Ghosh
Summary: By utilizing carbohydrate derivatives, fused 6/6 and 8/6 ring systems were successfully constructed through bicyclo annulations. The tricyclic structures obtained can be further functionalized to produce the tetracyclic sesterterpene variecolin.
Article
Chemistry, Organic
Shuowen Wang, Zhuohao Chen, Shanping Chen, Wen Shao, Ya Chen, Guo-Jun Deng
Summary: This study presents a novel and selective synthesis method for polycyclic fused maleimides from easily available raw materials under metal-free conditions.
Article
Chemistry, Organic
Shayan Sheykhi, Keyvan Pedrood, Massoud Amanlou, Bagher Larijani, Mohammad Mahdavi
Summary: This review discusses the formation of several polycyclic compounds via the intramolecular-Diels-Alder reaction, with a focus on the recent reactions using O-propargyl salicylaldehydes as starting material. Additionally, strategies for the synthesis of chromene-fused heterocycles are introduced and compared. The primary goal is to provide current information on the application of the intramolecular-Diels-Alder reaction in synthesizing a variety of chromene-fused heterocycles in recent chemical literature.
Article
Chemistry, Multidisciplinary
Kyu-Hyun Sim, Thameem ul Ansari, Yong-Gyu Park, Yeolib Jeong, Sang-Ha Oh, Hye-Won Min, Da-Yoon Jeon, Hyunwoo Kim, Cheon-Gyu Cho
Summary: This study reports the intramolecular Diels-Alder reactions of 2-pyrones with a chiral branched allylic silyl ether substituent, showing remarkably high pi-facial- and endo-selectivities. The resulting diastereomerically and enantiomerically pure cycloadducts were transformed into the natural products (+)-lycopladine A and (-)-lycoposerramine R.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Multidisciplinary Sciences
Min Jin, Congyun Tang, Yingying Li, Shuai Yang, Ying-Tao Yang, Lin Peng, Xiao-Nian Li, Wenjing Zhang, Zhili Zuo, Fabien Gagosz, Liang-Liang Wang
Summary: In this study, the authors present a catalytic asymmetric inverse-electron-demand-hetero-Diels-Alder reaction between neutral alkenes and alpha, beta-unsaturated ketones or aldehydes using a chiral phosphoric acid catalyst. This complex transformation allows for the formation of chiral fused heterocycles containing a central tetrahydropyran ring with high regio-, diastereo- and enantioselectivity. The stereocontrol achieved in this process is attributed to a key remote double hydrogen atom bonding interaction between the linear substrate and the catalyst.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Genesis Infante, Sara Eisler
Summary: Sequential anionic intramolecular cyclizations and modelling were used to access unusual fused heterocyclic frameworks in excellent yields for the first time. Regioselectivity in the cyclizations was controlled by exploiting stereoelectronic effects via n(C-)->pi*((Ph)) interactions, and modelling studies provided insights into the reaction scope.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Hongling Wang, Qiangqiang Zhang, Shuai Xiao, Guanjie Wang, Xuan Huang, Xingkuan Chen, Junmin Zhang
Summary: We have developed a N-heterocyclic carbene (NHC) and base-mediated [3 + 3] annulation reaction for the synthesis of enantioselective dihydropyrano[3,2-b]indoles. Easily prepared sulfonium salts were used as precursors and reacted with unsaturated acyl azolium to achieve this transformation. The reaction conditions are mild and result in privileged indole-fused dihydropyranones with moderate to good yields and excellent enantioselectivities.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Akil Hamsath, Oren L. Lederberg, Qi Cui, Meg Shieh, Yannie Lam, Brock J. Brummett, Shi Xu, Jerome R. Robinson, Ming Xian
Summary: An unprecedented intramolecular [4 + 2] tetrazine-olefin cycloaddition reaction was discovered, producing unique coumarin-dihydropyridazine heterocycles with excellent optical properties and stability. The reaction rate was solvent-dependent and studied using experimental data and kinetic modeling software. A release-then-click strategy based on ROS-triggered release was developed for the release of methylselenenic acid and a fluorescent tracer.
Article
Chemistry, Multidisciplinary
Song Xie, Jilai Wu, Likai Zhou, Chao Wei, Xiaoliu Li, Hua Chen
Summary: In this study, a series of novel fused multicyclic iminosugars were synthesized through a one-pot three-component stereoselective [4+2] reaction using D-ribose tosylate, aniline, and vinyl ethyl ether. The key intermediate for the reaction was identified as iminium ion. Different reaction temperatures led to the formation of complex fused iminosugars and aza-C-glycosides through aza-Diels-Alder and Mannich reaction, respectively, providing a strategy for the construction of structurally diverse and bioactive iminosugar analogues.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Matthew R. Hennefarth, Anastassia N. Alexandrova
Summary: External electric fields have been shown to be an effective tool in catalysis, influencing the thermodynamics and kinetics of reactions. By analyzing the topological features of heterogeneous electric fields within reactant states and quantum mechanical electron density, it is possible to predict reaction barriers and understand how external electric fields can inhibit or enhance reactions. This research paves the way for designing external fields for catalysis and predicting reactivity without explicit mechanistic interrogation across a variety of reactions.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Organic
Yang Li, Yongzhuang Wang, Xiaoli Huang, Yan Shi, Yuhai Tang, Jiao Jiao, Jing Li, Silong Xu
Summary: This highly efficient cascade cyclization reaction features a Ru(II)-catalyzed C-H activation initiated indole formation/Diels-Alder reaction/iminium ion cyclization sequence, providing hexacyclic indolines as single diastereomer in good to excellent yields with a broad substrate scope under mild conditions. The reaction allows for the simultaneous generation of five new chemical bonds and four new rings in one pot, offering a rapid and concise approach toward synthesizing polycyclic indoline alkaloids and their analogues.
Review
Chemistry, Multidisciplinary
Jan Maier, Todd B. Marder
Summary: The mechanism of the hexadehydro-Diels-Alder reaction (HDDA) is not simply described by a concerted or stepwise mechanism, with terminal substituents affecting reaction mechanism and kinetics and linkers influencing the HDDA reaction. Studies on yne-diynes reveal the impact of steric, electronic, and radical-stabilizing effects, while the recently discovered photochemical HDDA reaction may not proceed by the same mechanism as thermally generated ortho-arynes.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Yoshihiko Yamamoto, Motoji Sakai, Yuki Ishida, Takeshi Yasui
Summary: The synthesis of 1-(difluoromethyl)alkenes through palladium-catalyzed reaction showed high regioselectivity, with 1,3-dicarbonyl compounds attacking the gamma-carbon of allylic phosphates. Density functional theory (DFT) calculations revealed that the regioselectivity is attributed to the electronic environment of the unsymmetrical pi-allylpalladium intermediate. Further reactions with imides using a different catalyst system were also conducted.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Masatoshi Shibuya, Miki Matsuda, Yoshihiko Yamamoto
Summary: The study presents a novel single-step 1,2-dicarbofunctionalization method involving arylacetylene with an allylsilane and tris(pentafluorophenyl)borane [B(C6F5)(3)], leading to the formation of tetrafluoronaphthalenes. The unique reactivity of B(C6F5)(3) enables smooth reaction progress and can also result in ring opening in reactions with 2-substituted furan.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Takeshi Yasui, Keiji Yamada, Rine Tatsumi, Yoshihiko Yamamoto
Summary: In this study, a method for generating vinylallenes through cobalt/photoredox dual-catalysis was reported, allowing the formal 1,8-acyloxy migration of 1,6-diynyl esters. A cascade reaction involving 1,8-acyloxy migration/6 pi-electrocyclization was demonstrated using (hetero)aryl-substituted 1,6-diynyl esters, leading to the formation of arenol derivatives, and the method was also applied to cascade cyclizations involving [2 + 2] or [4 + 2] cycloadditions to furnish various polycyclic molecules.
Article
Chemistry, Physical
Takeshi Yasui, Rine Tatsumi, Yoshihiko Yamamoto
Summary: In this study, a dual cobalt and photoredox catalysis was utilized for the [2+2+2] cycloaddition of enediynes to produce tricyclic cyclohexadienes with a quaternary bridgehead carbon. The use of a chiral ligand, (S)-Segphos, enabled highly enantioselective reactions, leading to highly enantio-enriched cyclohexadienes.
Article
Chemistry, Organic
Yoshihiko Yamamoto, Yuya Nakazato, Ryu Tadano, Takeshi Yasui
Summary: This study reports the trifluoromethylation of furfural followed by photo-Achmatowicz reaction to obtain 6-hydroxy-2-(trifluoromethyl)-2H-pyran-3(6H)-one. The acetylated product, 6-acetoxy-2-(trifluoromethyl)-2H-pyran-3(6H)-one, was then transformed into various 1-(trifluoromethyl)-8-oxabicyclo[3.2.1]oct-3-en-2-one derivatives through a base-mediated oxidopyrylium [5 + 2] cycloaddition. The reactivity and selectivity of the 2-trifluoromethylated oxidopyrylium species were analyzed using density functional theory calculations.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Takeshi Yasui, Shouta Tanabe, Takuya Masueda, Yoshihiko Yamamoto
Summary: Here, a concise method for preparing functionalized cyclopentadienyl rhodium complexes via Suzuki-Miyaura cross-coupling is reported. The conversion of 2,3,4,5-tetramethylcyclopent-2-en-1-one into the cyclopentadienylboronic acid pinacol ester, which serves as a coupling partner with aryl halides, was successfully achieved. Various functionalized cyclopentadienyl rhodium complexes were synthesized from commercially available aryl bromides in two steps. Additionally, a novel chiral cyclopentadienyl rhodium complex was rapidly synthesized as a precatalyst for an asymmetric C-H functionalization reaction.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Yoshihiko Yamamoto, Syunji Tazawa, Ryu Tadano, Takeshi Yasui
Summary: Despite advances in trifluoromethylation methods, synthesizing complex trifluoromethylated molecules with a natural-product-like 3D structure is still challenging. This study investigated the cycloaddition of novel CF3-substituted oxidopyridinium betaines. By methylating trifluoromethylated pyridin-3-ols and reacting the generated pyridinium ions with triethylamine and N-methylmaleimide, trifluoromethylated 8-azabicyclo[3.2.1]octane derivatives were produced through a (5+2) cycloaddition. The regioselectivity and stereoselectivity of the reactions depended on the positions of the CF3 substituents, and computational investigations were conducted to gain further insight into the reactivity of trifluoromethylated oxidopyridinium betaines.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Organic
Yoshihiko Yamamoto, Yudai Shizume, Syunji Tazawa, Takeshi Yasui
Summary: By performing density functional theory (DFT) calculations and comparing with experimental results, we investigated the effects of N-substituents on the reactivity and selectivity of oxidopyridinium betaines in cycloadditions. Our findings demonstrated the applicability of 1-(2-pyrimidyl)-3-oxidopyridinium for (5 + 2) cycloadditions with various electron-deficient alkenes, dimethyl acetylenedicarboxylate, acenaphthylene, and styrene. Additionally, the analysis revealed the possibility of pathway bifurcations involving a (5 + 4)/(5 + 6) ambimodal transition state in the cycloaddition of 1-(2-pyrimidyl)-3-oxidopyridinium with 6,6-dimethylpentafulvene, although only (5 + 6) cycloadducts were observed experimentally. A related (5 + 4) cycloaddition was observed in the reaction of 1-(2-pyrimidyl)-3-oxidopyridinium with 2,3-dimethylbut-1,3-diene.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Review
Chemistry, Applied
Yoshihiko Yamamoto
Summary: Trifluoromethylated alkenes and alkynes are important building blocks for organofluorine synthesis and are found in biofunctional molecules. Although transition-metal-mediated reactions have been developed, more environmentally friendly synthesis methods are needed.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Tomohiro Kikuchi, Takeshi Yasui, Yoshihiko Yamamoto
Summary: Transition-metal mediated carbon-carbon single-bond cleavage of cyclopropenes has been achieved via an intramolecular cycloaddition with alkynes, leading to the formation of 1,2-fused cyclopentadienes. Fused cycloheptatrienes were also synthesized through the cycloaddition of cyclopropene-diynes.
Article
Chemistry, Multidisciplinary
Naohiro Hirako, Takeshi Yasui, Yoshihiko Yamamoto
Summary: 3,4-Fused 2-quinolone frameworks play important roles in natural products and biologically active compounds. Rh(III)-catalyzed alkenyl C-H functionalization of 4-amino-2-quinolones provides an efficient and selective approach to access these structural motifs.
Article
Chemistry, Organic
Yoshihiko Yamamoto, Harufumi Suzuki, Eisuke Kuroyanagi, Keiji Yamada, Takeshi Yasui
Summary: In this study, the atom transfer radical addition (ATRA) of bromodifluoroacetamides to arylalkynes and terminal alkenes was successfully conducted using von Wangelin's Co catalyst system. The corresponding functionalized difluoroacetamides were obtained in moderate to high yields. Additionally, the Co catalyst was applied to tandem addition/cyclization reactions of 1,6-diene and -enyne substrates, as well as intramolecular ATRA of N-allyl and N-propargyl bromodifluoroacetamides, significantly expanding the scope of radical difluoroalkylation.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Masatoshi Shibuya, Takayuki Orihashi, Yamei Li, Yoshihiko Yamamoto
Summary: The chemoselective benzylic C(sp(3))-H amination of unprotected arylalkanols catalyzed by N-hydroxyphthalimide has been successfully developed, with the critical role played by 1,1,1,3,3,3-hexafluoropropan-2-ol as a solvent. The conversion of the aminated product to the corresponding free amino alcohol was also demonstrated in this study.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Yoshihiko Yamamoto, Tomoya Takase, Eisuke Kuroyanagi, Takeshi Yasui
Summary: In this study, a new class of difluoromethylated diarylmethanes was synthesized through Fe(OTf)(3)-catalyzed reaction, demonstrating the relationship between substrate structure and catalyst behavior.
CHEMICAL COMMUNICATIONS
(2021)
