Article
Chemistry, Multidisciplinary
Melissa Ramirez, Dennis Svatunek, Fang Liu, Neil K. Garg, Kendall N. Houk
Summary: The Diels-Alder reactions of furans and pyrroles with 1,2-cyclohexadiene and oxa- and azaheterocyclic analogs exhibit endo selectivity, which is determined by the interaction of molecular orbitals and electrostatic effects. This selectivity, based on stabilizing interactions, is expected to lead to the increased use of strained cyclic allenes in chemical synthesis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Milauni M. Mehta, Jordan A. M. Gonzalez, James L. Bachman, Neil K. Garg
Summary: We present a method for constructing the core structure of the manzamine alkaloid keramaphidin B using a strain-promoted cycloaddition reaction. This method tolerates nitrile and primary amide functional groups, and can be followed by a retro-Diels-Alder reaction to increase structural complexity. These findings highlight the potential of strained cyclic allenes in building intricate structures, and provide inspiration for further studies on these transient intermediates.
Article
Chemistry, Multidisciplinary
Jie Lin, Minqiang Jia, Shengming Ma
Summary: The paper presents the successful development of the palladium-catalyzed exclusive 2,3-allenylation reaction of oxindoles with 2,3-allenylic carbonates, along with a proposed rationale for the selectivity of this reaction over the expected 1,3-alkadienylation.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Qing Sun, Tian-Yu Deng, Jia-Jie Chen, Jia-Yi Liu, Xin Lu, Zhi-Xia Zhang, Jin-Heng Li
Summary: The mechanism of Au(i)-catalyzed intermolecular annulation of 2-(1-alkynyl)-2-alken-1-one with N-allenamide has been elucidated using DFT. The key intermediate, a gold all-carbon 1,3-dipole species, is more reactive than the gold allylic carbocation. The influence of ligands and substituents has been analyzed.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Organic
Hai-Tao Zhu, Chun-Miao Liang, Ting-Yan Li, Lin-Yan Li, Rui-Ling Zhang, Jun-Na Wang, Rui-Qing Qi, Jia-Min Zhang, Ruo-Han Yang, Yin-Qi Yang, An-Xi Zhou, Xiaojie Jin, Ni-Ni Zhou
Summary: A one-pot step-economic tandem process involving (5 + 2)-cycloaddition and Nazarov cyclization reactions has been developed for the synthesis of indanone-fused benzo[cd]azulenes. The reaction is highly regio- and stereoselective and enabled by dual silver and Bronsted acid catalysis, providing a new avenue for the construction of important bicyclo[5.3.0]decane skeletons.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Multidisciplinary Sciences
Jie Wang, Wei-Feng Zheng, Xue Zhang, Hui Qian, Shengming Ma
Summary: This study reports the synthesis of non-readily available enantioenriched tetrasubstituted allenes through rhodium-catalyzed reactions controlled by steric hindrance. Detailed mechanistic experiments and density functional theory studies reveal the mechanism behind the formation of different stereochemistry under different reaction conditions. A stereodivergent protocol to construct the enantiomer of optically active tetrasubstituted allenes from the same starting materials is successfully developed based on these mechanistic understandings.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Chao Ning, Kang-Hua Rui, Yin Wei, Min Shi
Summary: In this study, the mechanism of Rh(i) complex catalyzed dimerization of ene-vinylidenecyclopropanes was elucidated through experimental and computational studies, and a key intermediate was identified.
Article
Chemistry, Physical
Marina A. Tokareva, Indrek Pernik, Barbara A. Messerle, Tatiana V. Glukhareva, Sinead T. Keaveney
Summary: Despite the growing use of denitrogenative reactions of 1,2,3-thiadiazoles in heterocycle synthesis, the origin of their varied reactivity and regioselectivity in transannulation reactions is not well understood. This study conducted systematic investigations on the Rh(i)-catalyzed intermolecular transannulation between substituted 1,2,3-thiadiazoles and phenylacetylene, revealing the significant influence of the electronic nature of the C5-substituent on reactivity and the remarkable effect of the substituent on regioselectivity. Density functional theory calculations supported and rationalized the experimental trends.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Organic
Yi Yang, Hui Wang, Zehua Sun, Xinjin Li, Fenggang Sun, Qing Liu, Lizhi Zhang, Liping Xu, Hui Liu
Summary: A palladium-catalyzed multi-component regiodivergent arylamination/aryloxygenation of allenamide has been reported. The choice of base plays a critical role in determining the chemoselectivity and regioselectivity of the reaction. Additionally, the reaction can lead to the formation of alkenes with excellent Z configuration, which is controlled by the steric hindrance of coordinated palladium intermediates.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Kang Lv, Xiaoguang Bao
Summary: In-depth mechanistic understanding of the Rh(i)-catalyzed transannulation of 1,2,3-thiadiazoles with alkenes, alkynes, and nitriles was gained through Density Functional Theory (DFT) calculations. The key intermediate in this reaction is suggested to be a four-membered cyclometalated Rh(iii) complex due to the easy chelation of the S atom with Rh. The regioselectivities in the product formation are not only determined by the feasible migratory insertion pathway, but also by the feasibility of the subsequent reductive elimination.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Ke-Qin Wu, Hui Li, Ao Zhou, Wei-Ran Yang, Qin Yin
Summary: A Pd-catalyzed regioselective C-H bond allylic alkylation of phenols with 1,3-dienes is reported, which selectively functionalizes the ortho C-H bond of 2-naphthols, 1-naphthols, and electron-rich phenols to synthesize phenol derivatives with diverse structures. The reaction is accelerated by a diphosphine ligand, does not require any other additive, and exhibits broad substrate scope and good chemo- and regioselectivity. Additionally, an asymmetric variant is investigated, achieving product with up to 55% enantiomeric excess.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Guan-Yu Zhang, Pan Zhang, Bing-Wen Li, Kang Liu, Jun Li, Zhi-Xiang Yu
Summary: Reported here is the Rh and Zn cocatalyzed [4 + 2] cycloaddition of newly designed yne-vinylcyclobutanones, which can generate bicyclic products with an all-carbon quaternary bridgehead center. Visual kinetic analysis and computational studies have been carried out to support the reaction mechanism and key steps involved.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Han Cao, Xuejing Liu, Fusheng Bie, Yijun Shi, Ying Han, Peng Yan, Michal Szostak, Chengwei Liu
Summary: The decarbonylative synthesis of thioethers from thioesters catalyzed by Rh is reported, showing excellent group tolerance to aryl chlorides and bromides without the need for phosphine ligands or inorganic bases. The methodology allows for gram scale synthesis, late-stage pharmaceutical derivatization, and orthogonal site-selective cross-couplings by C-S/C-Br cleavage.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Xin-Rui Zhu, De-Cai Fang
Summary: Density functional theory was used to investigate the mechanisms of Rh-catalyzed intramolecular [2 + 2 + 2] cycloaddition reactions. The reaction begins with the coordination of a Rh center in the catalyst to the alkyne in reactant 1a, followed by coordination to one of the double bonds in the allene, resulting in the formation of the first six-membered ring. There are two different reaction pathways, leading to the formation of [2 + 2 + 2] and [2 + 2] products, respectively. The energy span model suggests that the TOF-determining transition state (TDTS) and intermediate (TDI) are TS3 and INT2, resulting in an activation free-energy barrier of 32.1 kcal mol(-1) at a temperature of 383.75 K. The paper also discusses the substituent effect and intermolecular interaction energy.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Junjie Fan, Chunling Fu, Xiaoyan Wu, Shengming Ma
Summary: A novel synthetic method was reported for the coupling cyclization of different classes of allenes with 2,3-allenoic acids catalyzed by rhodium, leading to the formation of compounds with important bioactive components. The reaction involved nucleometalation, insertion, and stereodefined 1,4-H delivery processes carried out by the rhodium catalyst.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Yue Fu, Emily E. Zerull, Jennifer M. Schomaker, Peng Liu
Summary: Ag-catalyzed nitrene transfer reactions are important for converting C-H bonds into C-N bonds with diverse selectivity. Computational studies help understand the factors influencing reaction selectivity and provide insights for rational catalyst and precursor selection for regiodivergent amination reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Wang Yao, Gaoyuan Zhao, Yue Wu, Lin Zhou, Upasana Mukherjee, Peng Liu, Ming-Yu Ngai
Summary: This research reports a strategy using excited-state palladium catalysis for the 1,2-radical migratory Mizoroki-Heck reaction, enabling C2-alkenylation of carbohydrates with 1-bromosugars and alkenes. The reaction shows tolerance to various functional groups and complex molecular architectures and expands the reactivity profile of excited-state Pd catalysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Amit Kumar Simlandy, Warabhorn Rodphon, Turki M. Alturaifi, Binh Khanh Mai, Hui-Qi Ni, John A. Gurak Jr, Peng Liu, Keary M. Engle
Summary: A redox-neutral catalytic coupling of nitroalkanes and unactivated alkenes is reported in this study, which proceeds by a directed carbopalladation mechanism. The combination of PdI2 as the precatalyst and HFIP solvent enables the reaction uniquely. Structurally complex nitroalkane products, including nitro-containing carbo- and heterocycles, can be prepared under convenient conditions without the use of toxic or corrosive reagents. The reaction mechanism is examined through deuterium labeling experiments and isolation of a catalytically relevant intermediate. Different catalytic activation modes are utilized to demonstrate orthogonal methods for site-selective functionalization of a polyfunctional nitroalkyl ketone. Density functional theory (DFT) calculations reveal that the carbopalladation transition state is stabilized by a Na·I interaction and H·I hydrogen bond with HFIP.
Article
Chemistry, Multidisciplinary
Ruihan Wang, Yidong Wang, Ruiqi Ding, Parker B. Staub, Christopher Z. Zhao, Peng Liu, Yi-Ming Wang
Summary: A newly-developed cationic cyclopentadienyliron dicarbonyl complex enables the conversion of propylene to its allylic C-C bond coupling products under catalytic conditions. This approach is also applicable to the allylic functionalization of simple alpha-olefins with distinctive branched selectivity. Experimental and computational studies reveal the allylic deprotonation of the metal-coordinated alkene as the turnover-limiting step and provide insights into the multifaceted roles of the newly designed ligand in promoting allylic C-H functionalization with enhanced reactivity and stereoselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Changmin Xie, Jacob Kim, Binh Khanh Mai, Shixuan Cao, Rong Ye, Xin-Yi Wang, Peng Liu, Ohyun Kwon
Summary: This research describes a catalytic asymmetric reaction for the synthesis of chiral compounds using specific oxidants and reductants. The reaction is conducted under mild conditions and exhibits a wide substrate scope, high yield, and excellent enantioselectivity. The study also demonstrates the effectiveness of the designed catalyst and successfully synthesizes seven biologically active compounds.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Tobias Koengeter, Can Qin, Binh Khanh Mai, Qinghe Liu, Yucheng Mu, Peng Liu, Amir H. Hoveyda
Summary: This paper presents a stereoretentive strategy for catalytic cross-metathesis reaction between tri-, Z- or E-di, or monosubstituted olefins and Z- or E-2-bromo-2-butene, leading to the formation of various trisubstituted alkenyl bromides. The method is applicable for the generation of products containing polar moieties or sterically hindered alkenes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Amit Kumar Simlandy, Turki M. Alturaifi, Johny M. Nguyen, Lucas J. Oxtoby, Quynh Nguyen Wong, Jason S. Chen, Peng Liu, Keary M. Engle
Summary: We report a transient directing group (TDG) strategy for site-selective palladium-catalyzed reductive Heck-type hydroalkenylation and hydroalkynylation of alkenylaldehydes using alkenyl and alkynyl bromides. This strategy allows for the construction of a stereocenter at the delta-position with respect to the aldehyde. Computational studies reveal the beneficial roles of rigid TDGs, such as L-tert-leucine, in promoting TDG binding and inducing high levels of enantioselectivity in alkene insertion.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Hui-Qi Ni, Malkanthi K. Karunananda, Tian Zeng, Shenghua Yang, Zhen Liu, K. N. Houk, Peng Liu, Keary M. Engle
Summary: Multistep organic synthesis allows the conversion of simple chemical feedstocks into more complex products with specific functions. This study introduces a novel approach to organic reactions that can generate multiple valuable products with different carbon skeletons in a single operation. Through a palladium-catalyzed reaction, a single alkene starting material can be converted into two structurally distinct products, demonstrating the potential for simultaneous access to diverse compounds. The findings of this study provide insights into the mechanistic details of this unique catalytic system and establish a new method for small-molecule library synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jingfeng Huo, Yue Fu, Melody J. Tang, Peng Liu, Guangbin Dong
Summary: In this research, the first nickel-catalyzed Catellani-type annulation of aryl triflates and chlorides was achieved to form various benzocyclobutene-fused norbornanes in high efficiency. Mechanistic studies revealed an unexpected outer-sphere concerted metalation/deprotonation pathway and the essential roles of the base and the triflate anion. Compared to palladium catalysis, the reaction showed a broad functional group tolerance and enhanced regioselectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jicheng Wu, Peijing Jia, Rositha Kuniyil, Peng Liu, Weiping Tang
Summary: In this study, we report an efficient method for the stereoselective synthesis of challenging α-linked glycoconjugates using a Rh-II/chiral phosphoric acid (CPA)-cocatalyzed dynamic kinetic anomeric O-alkylation. By exploring various parameters of the cocatalytic system, we achieved excellent anomeric selectivity, excellent diastereoselectivity, broad substrate scope, and high efficiency for this glycosylation reaction. DFT calculations suggested that the anomeric selectivity was determined by steric interactions between the C2-carbon of the carbohydrate and the phenyl group of the metal carbenoid, while diastereoselectivity at the newly generated stereogenic center was influenced by π-π interactions with the C2-OBn substituent on the carbohydrate substrate.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Dennis A. Kutateladze, Binh Khanh Mai, Yuyang Dong, Yu Zhang, Peng Liu, Stephen L. Buchwald
Summary: A copper hydride-catalyzed approach has been developed for the synthesis of Z-configured trisubstituted alkenes with high stereo- and regioselectivity. This method provides a valuable strategy for accessing challenging classes of alkenes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Lei Cheng, Dian Li, Binh Khanh Mai, Zhiyu Bo, Lida Cheng, Peng Liu, Yang Yang
Summary: The merger of photoredox catalysis and PLP biocatalysis enables the development of a new synthetic method for preparing valuable noncanonical amino acids, allowing controlled formation of chiral products.
Article
Chemistry, Physical
Wenzhen Fu, Natalia M. M. Neris, Yue Fu, Yunlong Zhao, Benjamin Krohn-Hansen, Peng Liu, Yang Yang
Summary: This study describes a metalloredox biocatalysis strategy to repurpose natural cytochromes P450 for catalysing asymmetric radical cyclization to arenes through an unnatural electron transfer mechanism. Directed evolution yielded a series of engineered P450 aromatic radical cyclases with complementary selectivities. The excellent tunability of this metalloenzyme family provides an exciting platform for utilizing free radical intermediates in asymmetric catalysis.
Article
Chemistry, Physical
Amit Kumar Simlandy, Warabhorn Rodphon, Turki M. Alturaifi, Binh Khanh Mai, Hui-Qi Ni, John A. Gurak, Peng Liu, Keary M. Engle
Summary: We report a redox-neutral catalytic coupling of nitroalkanes and unactivated alkenes that proceeds by a directed carbopalladation mechanism. The reaction is enabled by the combination of PdI2 as the precatalyst and HFIP solvent. Complex nitroalkane products, including nitro-containing carbo- and heterocycles, can be prepared under convenient conditions without the need for toxic or corrosive reagents.
Article
Chemistry, Multidisciplinary
Gaoyuan Zhao, Upasana Mukherjee, Lin Zhou, Yue Wu, Wang Yao, Jaclyn N. Mauro, Peng Liu, Ming-Yu Ngai
Summary: This study reports the first direct strategy to synthesize C2-ketonyl-2-deoxysugars, important carbohydrate mimetics, from 1-bromosugars and silyl enol ethers via an excited-state palladium-catalyzed 1,2-spin-center shift process. The reaction is step-economic, has a broad substrate scope, high functional group tolerance, and can be used in the late-stage functionalization of natural product- and drug-glycoconjugates.
