Results 41 to 50 of about 32,974 (279)

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 π‐Extension of Helical PAHs: Tuning Energy Gaps and Excited‐State Dynamics Directed by Clar's Sextet Migration

Advanced Optical Materials, EarlyView.
Central and terminal ring fusions of per‐peri‐perbenzo[7]helicene (PB[7]H) yield novel helical polycyclic aromatic hydrocarbons (HPAHs). The migration of Clar's aromatic sextets governs the inner‐rim stiffness. This topology‐directed strategy bridges the discrete optical gaps of homologous series. Transition moment density (TMD) analysis visualizes the
Zhibo Liu, Zheng Zhang, Hikaru Sotome, Takashi Hirose   +3 more
wiley   +1 more source

Origin of the Anti-Markovnikov Hydroamination of Alkenes Catalyzed by L−Au(I) Complexes: Coordination Mode Determines Regioselectivity

, 2019
The reaction mechanism and regioselectivity for the gold(I)-catalyzed hydroamination reaction of terminal alkenes are analyzed by means of density functional theory (DFT) calculations.
Couce-Ríos, A., Lledós, A., Ujaque, G., Fernández López, Israel   +3 more
core   +1 more source

Cobalt/Photoredox Catalyzed Desymmetrization of Oxo and Azabicycles via Asymmetric Reductive Coupling With Alkynes

Advanced Science, EarlyView.
A one‐step, asymmetric reductive coupling of alkynes and oxa‐ and aza‐bicyclic olefins using a cobalt/photoredox catalytic system through desymmetrization. ABSTRACT Bicyclo[2.2.1]heptane frameworks represent a privileged structural motif prevalent in numerous natural products and bioactive molecules.
Subhankar Pradhan, Arko Saha, Bholanath Maity, Sayan Dutta, Luigi Cavallo, Basker Sundararaju   +5 more
wiley   +1 more source

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

Computation‐Guided Tunnel Engineering Enhances O2 Transport and H2O2 Resistance of Fe(II)/α‐Ketoglutarate‐Dependent Dioxygenases

Advanced Science, EarlyView.
This study presents a computational tunnel engineering strategy in Fe(II)/α‐ketoglutarate‐dependent dioxygenases (αKGDs) to enhance oxygen (O2) transport, an essential molecule for αKGDs, and limit hydrogen peroxide (H2O2) entry, an inhibitor from the αKG supply system.
Huan Liu, Lunjie Wu, Liying Mao, Songyin Zhao, Hu Liu, Shiyi Xin, Donglin Zhao, Jie Gu, Yan Xu, Xinye Wang, Yao Nie   +10 more
wiley   +1 more source

Regio‐ and enantioselective nickel-alkyl catalyzed hydroalkylation of alkynes

Nature Communications
The migratory insertion of metal-hydride into alkene has allowed regioselective access to organometallics, readily participating in subsequent functionalization as one conventional pathway of hydroalkylation, whereas analogous process with feedstock ...
Qian Gao, Wei-Cheng Xu, Xuan Nie, Kang-Jie Bian, Hong-Rui Yuan, Wen Zhang, Bing-Bing Wu, Xi-Sheng Wang   +7 more
doaj   +1 more source

Identify Regioselective Residues of Ginsenoside Hydrolases by Graph-Based Active Learning from Molecular Dynamics

Molecules
Identifying the catalytic regioselectivity of enzymes remains a challenge. Compared to experimental trial-and-error approaches, computational methods like molecular dynamics simulations provide valuable insights into enzyme characteristics.
Yi Li, Hong-Qian Peng, Meng-Liang Wen, Li-Quan Yang   +3 more
doaj   +1 more source

Unexpected reversal of the regioselectivity in Thermomyces lanuginosus lipase-catalyzed acylation of floxuridine

, 2009
Unexpected inversion of the 3':5'-regioselectivity was observed in the enzymatic methacryloylation, crotonylation and cinnamoylation of floxuridine (1.5:1, 2.3:1 and 4.4:1, respectively), where Thermomyces lanuginosus lipase preferentially catalyzed the ...
Li, Ning, Zong, Min-Hua, 马丁, Ma, Ding, Minhua Zong   +4 more
core   +1 more source

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]   +4 more
core   +1 more source