Article
Chemistry, Physical
Thomas M. Horsley Downie, Mary F. Mahon, John P. Lowe, Rowan M. Bailey, David J. Liptrot
Summary: The reaction of phosphorus(III) esters with pinacolborane using an NHC-copper(I) catalyst allows for the quick generation of various phosphines, which can be further used in the synthesis of different phosphorus-containing compounds. This telescoped approach provides access to a range of P-H bonded species with high conversions, enabling the synthesis of diverse phosphorus-based molecules without the need to handle toxic compounds.
Article
Chemistry, Multidisciplinary
Galla V. Karunakar, Chittala Emmaniel Raju, Karra Sai Bhavani Nagasri Himaja, Perla Bharath Kumar, Balasubramanian Sridhar
Summary: N-aryl-1H-pyrazolyl substituted benzenesulfonamide derivatives were regioselectively obtained from ynamides and pyrazoles through silver-catalyzed reaction. In this intermolecular organic transformation, several substituted benzenesulfonamides were obtained in good to excellent yields by forming a new C-N bond under mild reaction conditions.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Physical
Song Li, Haibei Li, Chen-Ho Tung, Lei Liu
Summary: This study reports a bio-inspired nonheme-iron-catalyzed method for the efficient and selective preparation of diversely functionalized organosilanols. The practical method allows for the synthesis of organosilanols with different substituent patterns and exhibits good functional group tolerance. The study also demonstrates the potential application of this method in the synthesis of functional molecules containing silanols.
Review
Chemistry, Multidisciplinary
Catriona C. James, Bas de Bruin, Joost N. H. Reek
Summary: The importance of transition metal catalysis lies in its wide range of applications, including the synthesis of chemicals, natural products, and pharmaceuticals. However, a relatively new application is the catalysis of new-to-nature reactions inside living cells. The complex environment of living cells poses challenges to transition metal catalysts due to the potential inhibition or deactivation by various biological components. In this review, we summarize the current progress in the field of transition metal catalysis, focusing on the evaluation of catalysis efficiency under living cell and biological conditions. Catalyst poisoning is a common issue in this field, and we suggest that future research should explore physical and kinetic protection strategies to enhance the reactivity of catalysts in cells.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Letter
Chemistry, Organic
Yumo Zhao, Yi Wan, Qiyang Yuan, Jinlian Wei, Yongqiang Zhang
Summary: A visible-light-induced photocatalytic C-Si formation strategy was developed using Martin's spirosilane-derived pentacoordinate silylsilicates as silyl radical precursors. The strategy exhibited efficient hydrosilylation of a wide range of alkenes and alkynes, as well as C-H silylation of heteroarenes. Notably, Martin's spirosilane was stable and could be easily recovered. Moreover, the reaction performed well using water as the solvent or low-energy green LEDs as an alternative energy source.
Review
Chemistry, Multidisciplinary
Zijuan Yan, Pan-Lin Shao, Qing Qiang, Feipeng Liu, Xuchao Wang, Yongjie Li, Zi-Qiang Rong
Summary: This article summarizes various mechanisms and reaction conditions for the transition metal-catalyzed conversion of aldehydes to ketones.
CHINESE CHEMICAL LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Cristian Cavedon, Sebastian Gisbertz, Susanne Reischauer, Sarah Vogl, Eric Sperlich, John H. Burke, Rachel F. Wallick, Stefanie Schrottke, Wei-Hsin Hsu, Lucia Anghileri, Yannik Pfeifer, Noah Richter, Christian Teutloff, Henrike Mueller-Werkmeister, Dario Cambie, Peter H. Seeberger, Josh Vura-Weis, Renske M. van der Veen, Arne Thomas, Bartholomaus Pieber
Summary: We demonstrate visible-light-mediated carbon-heteroatom cross-coupling reactions using a photoactive Ni(II) precatalyst. The activation of this precatalyst involves an initial intraligand charge transfer event triggered by visible light irradiation. Additionally, a porous, recyclable organic polymer for heterogeneous nickel catalysis of cross-coupling reactions is obtained through ligand polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Tesfaye Tebeka Simur, Tian-Yu Peng, Yi-Feng Wang, Xiu-Wei Wu, Feng-Lian Zhang
Summary: A boryl radical-promoted dehydroxylative alkylation of 3-hydroxy-oxindole derivatives is reported. The reaction involves the addition of DMAP-boryl radical to the amide carbonyl oxygen atom, causing a spin-center shift process that promotes C-O bond cleavage. The elimination of a hydroxide anion from a free hydroxy group is also achieved. The resulting carbon radical reacts with alkenes to furnish various C-3 alkylated oxindoles. This method offers a simple operation and broad substrate scope.
Article
Chemistry, Multidisciplinary
Lizhu Zhang, Cunbo Wei, Jiawen Wu, Dan Liu, Yinchao Yao, Zhuo Chen, Jianxun Liu, Chang-Jiang Yao, Dinghua Li, Rongjie Yang, Zhonghua Xia
Summary: This study demonstrates a new transition-metal and photocatalyst-free alkynylation reaction, which allows the coupling of iodoalkynes with (hetero)arenes or alkenes under visible-light irradiation. Mechanistic and computational studies reveal the process of visible light activation of iodoalkynes, and the mechanism of the reaction between the excited state iodoalkyne and C(sp(2))-H bonds to form products.
Article
Chemistry, Organic
Tesfaye Tebeka Simur, Tian-Yu Peng, Yi-Feng Wang, Xiu-Wei Wu, Feng-Lian Zhang
Summary: A boryl radical-promoted dehydroxylative alkylation of 3-hydroxy-oxindole derivatives is achieved by adding 4-dimethylaminopyridine (DMAP)-boryl radical to the amide carbonyl oxygen atom, inducing a spin-center shift process and promoting C-O bond cleavage. The elimination of a hydroxide anion from a free hydroxy group is also accomplished. Capture of the generated carbon radical with alkenes leads to a variety of C-3 alkylated oxindoles. This method offers a simple operation and broad substrate scope.
Article
Chemistry, Inorganic & Nuclear
Yiling Zhao, Yilin Chen, Li Zhang, Jiancheng Li, Yanbo Peng, Zhikang Chen, Liuyin Jiang, Hongping Zhu
Summary: Two borylaminoamidinatosilylenes were synthesized and their reactions towards isocyanides were investigated. The structures, compositions, and reaction mechanisms of the resulting compounds were determined through experiments and calculations.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Xinghao Sheng, Mingpan Yan, Bo Zhang, Wai-Yeung Wong, Nobuaki Kambe, Renhua Qiu
Summary: In this study, a mild and versatile nickel-catalyzed method for selectively functionalizing the C3 position of quinolines with various electrophiles was developed. Unactivated quinolines can be directly modified without the need for directing groups at room temperature. The reaction mechanism involves 1,4-addition of quinolines with nickel hydride species generated from β-H elimination of alkyl nickel intermediates, followed by subsequent nucleophilic attack and oxidative aromatization.
Review
Chemistry, Organic
Renzo Rossi, Maurizio Ciofalo
Summary: This review gives a comprehensive overview of the Pd-catalysed intermolecular direct C-H bond arylation of heteroarenes with arylating reagents. It summarizes the preparation of various arylating reagents, evaluates the practicality, versatility, and limitations of the arylation protocols, and compares the results with reactions using aryl halides as electrophiles. Mechanistic proposals are also discussed.
CURRENT ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Alexander Garay-Talero, Paola Acosta-Guzman, Diego Gamba-Sanchez
Summary: This manuscript presents a regioselective chlorination of arenes, yielding almost exclusively the monochlorinated product. It tolerates a wide range of functional groups and substituted aromatic rings, and demonstrates the utilization of chlorosulfonium salts as the chlorinating agent, avoiding the formation of organic byproducts.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Xin Liu, Yibin Hu, Yuanbin She, Meichao Li, Zhenlu Shen
Summary: A green and practical electrooxidation protocol has been developed for the C3 acyloxylation of 2H-indazoles with carboxylic acids. The reaction is sustainable without the use of transition-metal catalysts and stoichiometric oxidants. Potassium carbonate plays a key role in the reaction and reacts with carboxylic acids to form carboxylates. The reaction proceeds via an ECE mechanism, and various carboxylic acids and 2H-indazoles can be used to generate novel products at room temperature in an undivided cell.
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, Multidisciplinary
Min Zhu, Hua-Jie Jiang, Illia Sharanov, Elisabeth Irran, Martin Oestreich
Summary: A desymmetrizing silylation of aromatic diols is achieved by using List's counteranion directed silylation technique for asymmetric silyl ether formation of phenol derivatives. The enantioselective discrimination of achiral 1,1'-biaryl-2,6-diols is enabled by a silylium-ion-like silicon electrophile generated from an allylic silane paired with an imidodiphosphorimidate (IDPi). The enantioselectivity of the desymmetrization is further improved by a downstream kinetic resolution, converting the monosilylated minor enantiomer into the corresponding bissilylated diol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Benedikt Wolff, Martin Oestreich
Summary: This Review summarizes the approaches taken to achieve the stereoselective addition of nucleophiles to these fleeting intermediates, including recent advances where non-covalent interactions and chiral counterions are employed to discriminate either side of a trigonal-planar carbenium ion bearing three different substituents.
ISRAEL JOURNAL OF CHEMISTRY
(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)
