Review
Chemistry, Multidisciplinary
Emily K. Reeves, Emily D. Entz, Sharon R. Neufeldt
Summary: Chemodivergent cross-couplings refer to reactions in which one potentially reactive functional group can be made to react based on choice of conditions. Factors influencing selectivity include catalyst ligation state, solvent polarity, and metal identity.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Review
Chemistry, Organic
Xian Zhao, Wei Liu
Summary: Catalytic Sonogashira cross-coupling reactions are efficient and versatile for constructing complex alkynes from readily available starting materials. However, the development of transition-metal-catalyzed Sonogashira cross-coupling reactions of alkyl electrophiles is still limited. Current research focuses on the application of palladium, nickel, and copper catalysts, as well as achieving asymmetric Sonogashira cross-coupling reactions.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Physical
Amit Kumar Simlandy, Mao-Yun Lyu, M. Kevin Brown
Summary: The paper presents a method for synthesizing highly substituted spirocyclic cyclobutanes through catalytic arylation of cyclobutenes using Cu/Pd or Ni catalysts. The identification of a suitable Cu complex for arylboration is crucial for achieving high selectivity in Cu/Pd catalyzed reactions. The synthetic utility of the products is demonstrated, with mechanistic details discussed.
Article
Chemistry, Multidisciplinary
Dejiang Zhang, Liyuan Le, Renhua Qiu, Wai-Yeung Wong, Nobuaki Kambe
Summary: A strategy for the formation of antimony-carbon bond via nickel-catalyzed cross-coupling of halostibines was developed. This method has a wide substrate scope and is compatible with various functional groups. The successful synthesis of arylated stibine demonstrated the high synthetic potential of this transformation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Dmitry A. A. Dulov, Tatiana V. V. Magdesieva
Summary: It has been demonstrated that inexpensive and readily available N,N'-diaryldihydrophenazines can effectively replace Ir(III)- and Ru(II)-based photocatalysts in the dual photoredox/Ni(II)C-N coupling of aryl halides with a wide range of anilines, as shown by 32 examples. This efficient and operationally simple approach to diarylamines can be scaled up using a flow apparatus.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Chiara Palladino, Tommaso Fantoni, Lucia Ferrazzano, Beatrice Muzzi, Antonio Ricci, Alessandra Tolomelli, Walter Cabri
Summary: The copper-free Heck-Cassar-Sonogashira (HCS) reaction is a powerful method for C-C bond formation in organic synthesis and has several industrial applications. This study investigated the mechanism of the copper-free HCS reaction by conducting stoichiometric and catalytic reactions and analyzing the role of the base. The results showed that the base can accelerate the reduction of the precatalyst and decrease the energy barrier for the alkyne carbopalladation step.
Article
Chemistry, Physical
Robert Wethman, Joseph Derosa, Van T. Tran, Taeho Kang, Omar Apolinar, Anuji Abraham, Roman Kleinmans, Steven R. Wisniewski, John R. Coombs, Keary M. Engle
Summary: This study investigated the decomposition of primary sodium alkoxide salts under ambient storage conditions and its effects on commonly employed transition-metal-catalyzed cross-coupling reactions. Characterization of the main inorganic degradants was done using NMR, IR, and Raman spectroscopy, and it was found that CO2 in the air played a critical role in the decomposition process. The effects of storage conditions on decomposition were assessed, and preliminary experiments were conducted to understand the kinetics of this process.
Article
Chemistry, Organic
Guofu Zhang, Jing Wang, Chenfei Guan, Yiyong Zhao, Chengrong Ding
Summary: The synthesis of aryl phosphonates via nickel and palladium-catalyzed cross-coupling of aryl fluorosulfonates and phosphites is efficient and versatile, with good to excellent yields under mild conditions. This method can also directly convert phenols to aryl phosphonates, enhancing synthetic efficiency.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yifan Wang, Yuanyuan Ping, Wangqing Kong
Summary: A cooperative Pd/Cu-catalyzed three-component cross-coupling reaction of alkynes, B 2 Pin 2 and alkenetethered aryl halides is reported. This reaction proceeds under mild conditions and shows broad substrate scope, providing a variety of heterocycles containing tetrasubstituted alkenylboronate moieties in synthetically useful yields with excellent chemoselectivity and regioselectivity. An enantioselective cascade cyclization/cross-coupling process has also been developed for the synthesis of enantiomerically enriched oxindole bearing a tetrasubstituted alkenylboronate moiety.
CHINESE CHEMICAL LETTERS
(2023)
Article
Chemistry, Physical
Guang-Yan Xing, Ya-Cheng Zhu, Deng-Yuan Li, Pei-Nian Liu
Summary: On-surface synthesis, a powerful tool for atomically precise fabrication of low-dimensional carbon nanomaterials, has greatly enriched fundamental science and technology. Achieving high selectivity of covalent coupling reactions remains challenging due to the complicated reactivity of organic groups and irreversibility of covalent bonds. Only a few on-surface covalent coupling reactions are frequently used, and this Perspective focuses on the development and synthetic applications of on-surface cross-coupling reactions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Inorganic & Nuclear
Hojat Veisi, Bikash Karmakar, Pourya Mohammadi, Taiebeh Tamoradi, Saba Hemmati, Zeinab Joshani
Summary: In this review article, the application of metal nanoparticle-supported multiwalled carbon nanotubes (MWCNTs) in C-C and C-X (X = N, O, S) coupling reactions is discussed. These composites exhibit excellent catalytic performance in the formation of C-C and C-heteroatom bonds and can be easily isolated and recycled. The review highlights the potential and advantages of surface-engineered carbon nanotubes in organic cross-coupling reactions.
INORGANIC CHEMISTRY COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Akifumi Sumida, Kenta Ogawa, Hiroaki Imoto, Kensuke Naka
Summary: The relationship between the structure and steric/electronic properties of arsa-Buchwald ligands was investigated. It was found that the cyclopentyl group exhibited the highest catalytic activity for the SMC reaction, particularly with sterically hindered substrates.
DALTON TRANSACTIONS
(2023)
Review
Chemistry, Organic
Songlin Zheng, Yuanyuan Hu, Weiming Yuan
Summary: Transition-metal-catalyzed carbon-carbon cross-coupling reactions are significant in modern synthetic chemistry, but coupling two C(sp(3))-hybridized alkyl fragments has been challenging. Recent advancements in photoredox-mediated single-electron transmetalation have enabled selective manipulation of C(sp(3))-C(sp(3)) cross-coupling, offering new prospects in organic synthesis.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Multidisciplinary
Alasdair K. Cooper, Megan E. Greaves, William Donohoe, Paul M. Burton, Thomas O. Ronson, Alan R. Kennedy, David J. Nelson
Summary: A nickel/dppf catalyst system successfully achieved Suzuki-Miyaura cross-coupling reactions of certain chloropyridines and chloroquinolines but not others, due to differences in the reaction mechanism. Chloropyridines rapidly undergo oxidative addition to the catalyst, while alpha-halo-N-heterocycles form catalytically inactive dimeric nickel species.
Article
Chemistry, Multidisciplinary
Nina V. Kuchkina, Svetlana A. Sorokina, Alexey V. Bykov, Mikhail G. Sulman, Lyudmila M. Bronstein, Zinaida B. Shifrina
Summary: The use of PEGylated nanocomposite catalysts has successfully stabilized Pd2+ complexes and Pd nanoparticles, demonstrating excellent catalytic activity in copper-free Sonogashira and Heck cross-coupling reactions. The reactions exhibit high yields in green solvents with low palladium loading and allow for easy magnetic separation and reuse without significant decrease in catalytic activity.
Article
Chemistry, Multidisciplinary
Zhi-Yuan Zhao, Ming Cui, Elisabeth Irran, Martin Oestreich
Summary: This study successfully achieved highly enantioselective silylation of 3-substituted 2H-azirines using a copper-catalyzed reaction with a silyl boronic ester as a latent silicon nucleophile. The resulting C-silylated, unprotected (N-H) aziridines were obtained in high yields and with excellent enantioselectivities, and they can be further converted into valuable compounds without significant loss of enantiomeric excess.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Yi Peng, Martin Oestreich
Summary: Opening the ring of cyclic amines by selectively breaking the carbon-nitrogen bond greatly expands the range of available nitrogen-containing structures. However, methods that can directly open secondary amines are limited. This study presents an efficient reductive ring opening of cyclic amines using PhSiH3 under B(C6F5)(3) catalysis, allowing for the transformation of unstrained cyclic amines into acyclic amines in a simple one-step process. Experimental evidence supports a stepwise mechanism involving silylammonium ions and reductive cleavage of carbon-nitrogen bonds.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Tao He, Hendrik F. T. Klare, Martin Oestreich
Summary: The method of methylation of various arenes with methanol is disclosed. The reaction is initiated by counteranion-stabilized silylium or arenium ions, which form Meerwein's salt-like oxonium ions with methanol as the active methylating agents. The silylated methyloxonium ions are stronger electrophiles than their protonated congeners, allowing the Friedel-Crafts alkylation to proceed more efficiently and at a lower reaction temperature. The regeneration of these superelectrophiles within the catalytic cycle is accomplished by the addition of a tetraorganosilane additive, that releases a silylium ion through protodesilylation by the Bri nsted acidic Wheland intermediate, thereby acting as a productive proton-into-silylium ion generator. By this method, even the C-H methylation of electronically deactivated aryl halides with methanol is achieved. The protocol is also applicable to nonactivated primary as well as pi-activated benzylic alcohols. Dialkyl ethers are also competent alkylating agents in the presence of the quaternary phenylsilane additive.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Supriya Rej, Hendrik F. T. Klare, Martin Oestreich
Summary: Geminal alkenes with an aryl and an allenyl group exhibit the structure of [3]dendralenes. The central alkene double bond in these polyenes can react with a silylium ion, initiating a Nazarov cyclization. The resulting ionic intermediate is captured by hydride in the presence of excess hydrosilane. The benzannulated methylenecyclopentene derivatives with a silylalkyl group then undergo silylium-ion regeneration and an unusual endo-selective intramolecular hydrosilylation. This cascade reaction eventually leads to the formation of a silicon-containing bicyclo[3.2.1]octane skeleton.
Review
Chemistry, Organic
Nektarios Kranidiotis-Hisatomi, Martin Oestreich
Summary: Enantioconvergent transition-metal-catalyzed cross-coupling reactions of racemic a-silyl and a-boryl reagents are important for the synthesis of highly enantioenriched a-chiral silanes and boranes. Palladium, nickel, and copper catalysis are used with a-silyl and a-boryl electrophiles. Numerous chiral ligands have extended the scope of this field. This review summarizes the progress made in this rapidly evolving area.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Organic
Avijit Roy, Haopeng Gao, Hendrik F. T. Klare, Martin Oestreich
Summary: The electrophilic silylium ions were used to investigate the intramolecular Friedel-Crafts-type cyclization of aryl tethered 1,1-difluoroalkenes. The preference for electrophilic silylation of the carbon-carbon double bond over vinylic C(sp(2))-F bonds activation initiates the reaction. Subsequent cyclization and hydrodefluorination of the resulting C(sp(3))-F bonds produce the final product in moderate to good yields. Unlike previous reports, the reaction proceeds with perfluorinated tetraphenylborate counteranion under ambient conditions without the need for a carborate counteranion associated with the silylium ion intermediates.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Organic
Lucie Finck, Sarah Dabrowski, Martin Oestreich
Summary: A denitrogenative palladium-catalyzed C(sp(2))-C(sp(2)) cross coupling reaction of aryl-substituted diazenes capped with a trimethylsilyl group and functionalized aryl bromides is described. The use of a PEPPSITM catalyst in the presence of NaOt-Bu enables the activation of the N-aryl-N'-silyldiazene pronucleophile, leading to the loss of dinitrogen and subsequent coupling with the in-situ-formed aryl nucleophile. This methodology provides access to biaryl compounds with various substituents.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Benedikt Wolff, Zheng-Wang Qu, Stefan Grimme, Martin Oestreich
Summary: This study presents a method for the enantioselective reduction of simple carbenium ions using cyclohexadienes with a hydridic C-H bond at an asymmetrically substituted carbon atom. Chiral cyclohexadienes are used as dihydrogen surrogates for the transfer hydrogenation of alkenes (styrenes). The reaction mechanism involves the initiation by trityl cation and a delicate intermolecular capture of a carbenium-ion intermediate by the chiral hydride source, resulting in good enantiomeric ratios of the reduction products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Honghua Zuo, Hendrik F. T. Klare, Martin Oestreich
Summary: A catalytic silylium-ion-promoted intramolecular alkyne carbosilylation reaction is reported, involving electrophilic activation of the C-C triple bond by a silylium ion and maintenance of the catalytic cycle through protodesilylation of an allylsilane reagent. The reaction exhibits exclusive 7-endo-dig selectivity and results in fully substituted vinylsilane derivatives of silylated benzocycloheptenes. Control experiments demonstrate that the catalytically active silylium ion can be regenerated by protodesilylation of the vinylsilane product.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Daniel Broesamlen, Martin Oestreich
Summary: A newly developed hept-4-yl-substituted Pybox ligand enables a nickel-catalyzed enantio- and regioconvergent alkylation of regioisomeric mixtures of racemic germylated allylic electrophiles with alkyl nucleophiles, yielding various chiral gamma-germyl alpha-alkyl allylic building blocks with excellent yields and enantioselectivities. The regioconvergence is attributed to the steering effect of the bulky germyl group. The resulting vinyl germanes can be easily halodegermylated without racemization of the allylic stereocenter, providing synthetically valuable gamma-stereogenic vinyl halides.
Article
Chemistry, Organic
Daniel Bro''samlen, Martin Oestreich
Summary: A Ni-H-catalyzed hydroalkylation of vinylsilanes and -germanes as well as allylsilanes with unactivated alkyl iodides is described. In contrast to reactions with styrene or vinyl boronate esters, the addition across the C-C double bond exhibits anti-Markovnikov selectivity, yielding the linear regioisomer. Mechanistic control experiments confirm a radical mechanism, and a competition experiment demonstrates the chemoselectivity favoring the vinyl group over the allyl group.
Article
Chemistry, Organic
Peng-Wei Long, Tao He, Hendrik F. T. Klare, Martin Oestreich
Summary: This Account summarizes the fascinating chemistry of cyclopropyl-stabilized silylium ions, which can be readily obtained from vinyl-cyclopropanes (VCPs). Depending on the nucleophilic partner, these reactive intermediates undergo direct ring opening or ring expansion, leading to the formation of nonclassical alkene-stabilized silylium ions. The latter can also be obtained by gold and proton electrophiles from silicon compounds containing unsaturated C-C bonds. These reaction cascades can be terminated by the formation of C-H or C-C as well as Si-O bonds, revealing the versatility of these complex reactions.
Article
Chemistry, Physical
Min Zhu, Martin Oestreich
Summary: A group-selective monosilylation of silanediols using List's counteranion-directed silylation methodology is described. The enantioselectivity is achieved by generating a silylium-ion-like silicon electrophile from an allylic silane paired with an imidodiphosphorimidate (IDPi), enabling discrimination of the two hydroxy groups attached to the prochiral silicon atom. Furthermore, the enantioselectivity is improved by a subsequent kinetic resolution, resulting in silicon-stereogenic disiloxanes with high enantiocontrol.
Article
Chemistry, Multidisciplinary
Yuanjiu Xiao, Lei Tang, Tong-Tong Xu, Jiang-Yi-Hui Sheng, Zhongyan Zhou, Lei Yue, Guoqiang Wang, Martin Oestreich, Jian-Jun Feng
Summary: A boron Lewis acid-catalyzed intermolecular carboacyloxylation of ynamides with esters is reported, which provides a direct and efficient way to access fully substituted acyclic enol esters. The reaction shows high regio- and Z/E selectivity and is compatible with readily available allylic carbonates. This strategy allows the construction of acyclic beta,beta-disubstituted enol carbonates of amides and can be applied to the synthesis of enantioenriched alpha-quaternary amides.
Review
Chemistry, Organic
Lucie Finck, Martin Oestreich
Summary: This perspective provides an overview of the underexplored chemistry of diazenes and highlights their potential in synthetic transformations. The stability and reactivity of diazenes have been enhanced by using silicon protection. The generation of aryl, diazenyl, and alkyl anionic intermediates under catalytic conditions opens up new synthetic approaches as alternatives to existing methodologies.
JOURNAL OF ORGANIC CHEMISTRY
(2023)