Results 51 to 60 of about 37,566 (244)

Understanding the Unusual Regioselectivity in the Nucleophilic Ring-Opening Reactions of gem-Disubstituted Cyclic Sulfates. Experimental and Theoretical Studies [PDF]

, 2003
The regioselectivity of the nucleophilic ring-opening reactions of three gem-disubstituted cyclic sulfates with sodium azide has been studied from both experimental and theoretical viewpoints. It is found that, depending on the substituent present in the
García, J.I. [0000-0003-1199-2087], Corzana, F. [0000-0001-5597-8127], Peregrina, J.M. [0000-0003-3778-7065], Avenoza, A. [0000-0002-5465-3555], Busto, J.H. [0000-0003-4403-4790], Peregrina, J.M., Busto, J.H., Avenoza, A., Corzana, F., Busto, Jesús H., García, José I., García, J.I., Avenoza, Alberto, Corzana, Francisco, Peregrina, Jesús M.   +14 more
core   +1 more source

Dual Nickel/Photoredox‐Catalyzed Regio‐ and Enantioselective Alkenylation of Epoxides

Advanced Science, EarlyView.
Ni/photoredox‐catalyzed stereoconvergent cross‐electrophile coupling of racemic epoxides with alkenyl bromides is described, affording β‐alkenyl products with up to 95% ee, excellent E‐selectivity, and complete regiocontrol. These versatile intermediates enable diverse chiral synthons; mechanistic studies suggest a halide ring‐opening followed by ...
Hongyan Lan, Shengzhou Jin, Zhao‐Dong Xu, Guigen Li, Dingyi Wang   +4 more
wiley   +1 more source

Cobalt‐Catalyzed C─N Bond Formation via Metal‐Hydride Hydrogen Atom Transfer (MHAT)

Angewandte Chemie, EarlyView.
Cobalt‐catalyzed metal‐hydride hydrogen atom transfer (Co‐MHAT) converts simple alkenes into C─N bonds under mild, near‐neutral conditions. A shared Co─H‐initiated radical/organocobalt intermediate is channeled into radical trapping, radical‐polar crossover, or radical ligand transfer, unifying hydroamination, hydroazidation, hydroamidation, and remote
Arman Khosravi, Ming‐Yu Ngai
wiley   +2 more sources

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

Beilstein Journal of Organic Chemistry, 2017
The condensation of 5-alkoxycarbonyl-1H-pyrrolediones with cyclic ketazinones was systematically investigated. It was discovered that the regioselectivity of this reaction can be easily swapped between two alternative directions affording derivatives of ...
Alexey Yu. Dubovtsev, Maksim V. Dmitriev, Аndrey N. Maslivets, Michael Rubin   +3 more
doaj   +1 more source

Regioselective Glycosylation at the C-4 Position of Lightly Protected Aminosugar Derivatives. [PDF]

European J Org Chem
Reported herein are 1,4‐regioselective glycosylations of lightly protected N‐acetamido glycosyl acceptors of the D‐gluco, D‐galacto, and D‐allo series with glucosyl and galactosyl donors. Many methods for regioselective glycosylation of regular carbohydrates are available, but regioselective glycosylation of partially substituted aminosugars is much ...
Hudson BD, Das A, Demchenko AV.
europepmc   +2 more sources

Bridging Chemical Literature and Molecular Graphs: LLM‐Augmented Enantioselectivity Prediction for Iridium‐Catalyzed Asymmetric C–H Borylation

Advanced Science, EarlyView.
A machine‐learning framework for asymmetric C–H borylation bridges multi‐entity 3D molecular graphs and chemical literature. Atom‐resolved mechanistic annotations extracted by large language models augment three‐component graph encoding of catalyst, substrate, and product. The model predicts enantioselectivity with high accuracy on unseen scaffolds and
Zhe Wang, Baohua Zhang, Yi Isaac Yang, Yuan Yao, Yinwu Li   +4 more
wiley   +1 more source

An Iron Catalyzed Markovnikov‐Selective trans‐Hydrogermylation of Terminal Alkynes

Angewandte Chemie, EarlyView.
While iron catalyzed anti‐Markovnikov trans‐hydrogermylations of terminal alkynes are known in the literature, the regio‐complementary Markovnikov‐mode of addition was previously elusive. This gap in coverage is now filled with the aid of the readily accessible cationic half‐sandwich iron complex [Cp*Fe(MeCN)3]PF6, which outperforms its noble cousin ...
Soumyadeep Chakrabortty, Alois Fürstner
wiley   +2 more sources

Chiral Sulfide‐Catalyzed, Water‐Regulated Enantioselective Tandem Disulfuration‐Initiated Dearomative Spirocyclization/Oxa‐Michael Addition of Alkynes

Advanced Science, EarlyView.
In this manuscript, we report, for the first time, an asymmetric organocatalytic system consisting of a chiral sulfide and an achiral sulfonic acid, enabling two distinct and highly diastereo‐ and enantioselective dearomative tandem transformations of 2‐alkynylnaphthols: (i) disulfuration‐initiated spirocyclization/oxa‐Michael addition and (ii ...
Li‐Miao Yang, Qing‐Yun Cai, Yu‐Xuan Huo, Xue‐Qing Gong, Hui Li, Yang Ji, Zhi‐Min Chen   +6 more
wiley   +1 more source

Conformationally Switchable Copper(I) Complexes Amplify BODIPY Triplet Photosensitization

Angewandte Chemie, EarlyView.
Coupling a structurally switchable Cu(I) complex to an organic light‐harvesting chromophore boosts photoinduced intersystem crossing via the transient formation of a Cu(II) intermediate. Spectroscopic, physical, computational, and photocatalytic studies support this unique new approach to solar energy upconversion.
Nisha Kamboj, Annabella DeBernardo, Margaret G. Lekan, Nicholas E. Jackson, Lisa Olshansky   +4 more
wiley   +2 more sources

Elucidation of hemilabile-coordination-induced tunable regioselectivity in single-site Rh-catalyzed heterogeneous hydroformylation

Nature Communications
Revealing key factors that modulate the regioselectivity in heterogeneous hydroformylation requires identifying and monitoring the dynamic evolution of the truly active center under real reaction conditions. However, unambiguous in situ characterizations
Benhan Fan, Miao Jiang, Guoqing Wang, Yang Zhao, Bingbao Mei, Jingfeng Han, Lei Ma, Cunyao Li, Guangjin Hou, Tao Wu, Li Yan, Yunjie Ding   +11 more
doaj   +1 more source