Article
Chemistry, Physical
Xin-Shen Liang, Rui-Dong Li, Wei Sun, Zhong Liu, Xiao-Chen Wang
Summary: Borane-mediated hydride abstraction has been shown to be a powerful tool for the C(sp(3))-H functionalization of amines, but its activity with ethers is still unknown. In this study, we discovered this activity in 2H-chromenes and established a catalytic C(sp(3))-H functionalization reaction using silyl ketene acetals as nucleophiles.
Article
Chemistry, Multidisciplinary
Tobias Wagener, Lukas Lueckemeier, Constantin G. Daniliuc, Frank Glorius
Summary: This study successfully demonstrates the synthesis of sought-after, enantioenriched delta-lactams through an interrupted hydrogenation mechanism using oxazolidinone-substituted pyridines and water.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Ming Zhang, Xiao-Chen Wang
Summary: This method presents a mild and efficient approach for synthesizing enantioenriched tetrahydroquinoline-fused cyclobutenes through a cascade reaction, catalyzed by chiral spiro-bicyclic bisboranes. The bisboranes function by catalyzing hydride transfer and activating the alkynone substrate for an enantioselective cycloaddition reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Chemistry, Applied
Sven E. Prey, Matthias Wagner
Summary: This review compares the activation effects of four different types of 1,4-diborabenzene derivatives on three model substrates and analyzes the factors influencing the activation. By studying the conversion reactions of model substrates, a better understanding of the reaction behavior of these diboracycles towards more complex substrates is achieved.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Max Wienhold, John J. Molloy, Constantin G. Daniliuc, Ryan Gilmour
Summary: Modular beta-borylacrylates have been shown to play a crucial role in generating diverse coumarins, with the BPin unit enabling the cascade annulation of 2-halo-phenol derivatives. Mild isomerisation allows for the synthesis of structurally varied coumarins, and the method has potential applications in bioassay development and drug repurposing.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Sofia Siciliano, Elena Cini, Maurizio Taddei, Giorgia Vinciarelli
Summary: The synthesis of 2-substituted indoles from unprotected 2-alkynylanilines using Pd(OAc)(2) catalyst in 3% TPGS-750-M water was found to be sensitive to the heating mode and the MW delivery mode, with convectional heating often proving more effective than microwave dielectric heating. Additionally, a tandem Sonogashira-cyclisation reaction was successfully achieved in the nanomicellar water environment with Pd(OAc)(2)/Xphos.
Article
Chemistry, Multidisciplinary
Anand B. Shabade, Dipesh M. Sharma, Priyam Bajpai, Rajesh G. Gonnade, Kumar Vanka, Benudhar Punji
Summary: Chemoselective hydrogenation of C=C, C=O and C=N bonds in alpha,beta-unsaturated ketones, aldehydes and imines can be achieved at room temperature using a well-defined Mn(I) catalyst and hydrogen gas. The method shows tolerance towards various sensitive functional groups and can be applied to unsaturated ketones containing indole, pyrrole, furan, thiophene, and pyridine moieties. In the reaction, the C=C bond is selectively hydrogenated, while the C=O and C=N bonds in aldehydes and imines are preferentially reduced.
Article
Chemistry, Multidisciplinary
Vibha V. Kanale, Christopher Uyeda
Summary: Cobalt catalysts facilitate highly enantioselective ring-opening reactions of 2,5-dihydrofurans using vinylidenes. The resulting products are acyclic organozinc compounds, capable of further functionalization with an electrophile. The proposed mechanism involves the formation of a cobalt vinylidene species that adds to the alkene via a [2+2]-cycloaddition pathway, followed by ring-opening through outer-sphere & beta;-O elimination assisted by a ZnX2 Lewis acid. DFT models explain the observed stereochemical outcome by suppressing competing inner-sphere syn & beta;-H and & beta;-O elimination pathways due to the geometric constraints of the metallacycle intermediate. Cobalt catalysts also promote enantioselective ring-opening reactions of unstrained heterocycles via reductive addition of 1,1-dichloroalkenes. The resulting products are acyclic homoallylic alcohols with a vinylzinc motif, which can be further modified with an electrophile. Mechanistic studies suggest that the ring-opening occurs through outer-sphere & beta;-O elimination facilitated by a Zn(II) Lewis acid.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Mingxin Liu, Nguyen Le, Christopher Uyeda
Summary: Nickel catalysts promote nucleophilic cyclopropanation reactions using CH2Cl2 as a methylene source and Mn as a stoichiometric reductant. The substrate scope includes a broad range of alkenes bearing electron-withdrawing substituents, and enantioselective cyclopropanations have been developed using chiral PyBox ligands. Mechanistic studies suggest the intermediacy of a (PyBox)Ni=CH2 species and DFT models provide a rationale for the nucleophilic character of the nickel carbene and the sense of enantioinduction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Johannes Grosskopf, Thorsten Bach
Summary: Upon irradiation with a suitable chiral catalyst, racemic compounds can be converted into enantiopure compounds through a process called photochemical deracemization. This review comprehensively covers the research and current developments in this field, discussing the reactions and mechanistic details underlying the presented reaction. Photochemical deracemization offers a unique opportunity to directly obtain enantiopure compounds from racemates, and short-lived intermediates play a key role in determining the enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Florian Bourriquen, Julien Hervochon, Stephan Bartling, Nils Rockstroh, Ceidric Fischmeister, Kathrin Junge, Matthias Beller
Summary: A methodology for regiodivergent hydrogenation of quinolines is presented using readily available and commercial supported ruthenium catalysts. cis- or trans-Decahydroquinolines can be obtained with high yield and high diastereoselectivity by adjusting the catalyst or reaction temperature. Heterogeneous ruthenium catalysts are reported for practical regiodivergent hydrogenation of quinolines.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Organic
Zi-Qi Yi, Fei Chen, Yan-Mei He, Qing-Hua Fan
Summary: A general asymmetric hydrogenation of isoquinolines catalyzed by chiral cationic ruthenium catalysts has been investigated. Various isoquinoline derivatives were efficiently hydrogenated to give chiral tetrahydroisoquinolines with high enantioselectivity. Preliminary mechanistic studies revealed a stepwise reduction pathway for isoquinolines.
Article
Chemistry, Multidisciplinary
James E. Baumann, Gojko Lalic
Summary: A new method for the differential dihydrofunctionalization of terminal alkynes has been developed, enabling the synthesis of allylic boronate esters through a reductive three-component coupling reaction. This transformation, promoted by a copper/palladium catalyst system, hydrofunctionalizes both pi-bonds of the alkyne. The method is compatible with a wide range of functional groups.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Josep Mas-Rosello, Christopher J. Cope, Eric Tan, Benjamin Pinson, Alan Robinson, Tomas Smejkal, Nicolai Cramer
Summary: Cyclometalated cyclopentadienyl iridium(III) complexes are efficient catalysts in the hydrogenation of oximes, with alkoxy-substituted aryl ketimine ligands providing the best catalytic performance. The stable iridium C,N-chelation is crucial for the catalytic activity, and the hydrogenation system demonstrates high functional group compatibility.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Chemistry, Organic
Pascal Matton, Steve Huvelle, Mansour Haddad, Phannarath Phansavath, Virginie Ratovelomanana-Vidal
Summary: Metal-catalyzed [2+2+2] cycloaddition is a powerful method for the rapid construction of functionalized 6-membered carbo- and heterocycles with high functional group tolerance. The reaction is usually regio- and chemoselective, but challenges remain for intermolecular reactions involving multiple alkynes.
SYNTHESIS-STUTTGART
(2021)
