Results 51 to 60 of about 32,974 (279)

Pd‐Catalyzed Asymmetric Dearomative Heck/Tsuji‐Trost Difunctionalization of Naphthalenes

Advanced Science, EarlyView.
We have developed a palladium‐catalyzed asymmetric dearomative Heck/Tsuji‐Trost 1,4‐difunctionalization reaction of naphthalenes, affording 4‐aminospirocyclohexene oxindole products bearing two remote chiral centers. Through the effect of the newly designed chiral sulfinamide phosphine ligand with large steric hindrance, side reactions are inhibited ...
Long‐Ling Ma, Bing Xu, Junliang Zhang, Zhan‐Ming Zhang   +3 more
wiley   +1 more source

Relative Strength of Common Directing Groups in Palladium-Catalyzed Aromatic C−H Activation

iScience, 2019
Summary: Efficient functionalization of C−H bonds can be achieved using transition metal catalysts, such as Pd(OAc)2. To better control the regioselectivity in these reactions, some functional groups on the substrate may be used as directing groups ...
Anna Tomberg, Michael Éric Muratore, Magnus Jan Johansson, Ina Terstiege, Christian Sköld, Per-Ola Norrby   +5 more
doaj   +1 more source

Unveiling the Origin of the Selectivity and the Molecular Mechanism in the [3+2] Cycloaddition Reaction of N-aryl-C-carbamoylnitrone with N-arylitaconimide

Organics, 2022
The [3+2] cycloaddition reaction of N-aryl-C-carbamoylnitrone (nitrone 1) with N-arylitaconimide (ethylene 2) was computationally studied using the B3LYP/6-31G(d) level of theory. An analysis of the different energetic profiles and the transition states’
Abdelmalek Khorief Nacereddine, Fouad Chafaa   +1 more
doaj   +1 more source

On the mechanism of the Shapiro reaction: Understanding the regioselectivity

, 2015
A detailed DFT-level mechanism elucidation of the two-step reaction of tosylhydrazones with alkyllithium reagents (the Shapiro reaction) is presented.
Funes-Ardoiz, I. [0000-0002-5843-9660], Sampedro, D. [0000-0003-2772-6453], Losantos, R. [0000-0001-5207-654X]   +2 more
core   +1 more source

Design and Engineering of an Artificial Bifunctional N‐Deacetylase/N‐Sulfotransferase for the Biosynthesis of N‐Sulfated Heparosan

Advanced Science, EarlyView.
An artificial bifunctional N‐deacetylase/N‐sulfotransferase was engineered in Escherichia coli by combining screened N‐deacetylases with an NST domain. The integrated engineering strategy improved enzyme performance. The optimized enzyme efficiently converted heparosan into N‐sulfated heparosan, addressing a key bottleneck in microbial heparin ...
Xintong Xi, Ruirui Xu, Daoan Wang, Guobin Yin, Xinjing Wang, Haiqin Chen, Guocheng Du, Jian Chen, Zhen Kang   +8 more
wiley   +1 more source

Ligand-controlled regiodivergent arylation of aryl(alkyl)alkynes and asymmetric synthesis of axially chiral 9-alkylidene-9,10-dihydroanthracenes

Nature Communications
Transition metal-catalyzed addition of organometallics to aryl(alkyl)alkynes has been well known to proceed with the regioselectivity in forming a carbon–carbon bond at the alkyl-substituted carbon (β-addition).
Chao Sun, Ting Qi, Faiz-Ur Rahman, Tamio Hayashi, Jialin Ming   +4 more
doaj   +1 more source

A Simple and Easily Implemented Method for the Regioselective Introduction of Deuterium into Azolo[1,5-a]pyrimidines Molecules

Molecules, 2023
A method for the technically easy-to-implement synthesis of deuterium-labeled pyrazolo[1,5-a]pyrimidines and 1,2,4-triazolo[1,5-a]pyrimidines have been developed. The regioselectivity of such transformations has been shown.
Gevorg G. Danagulyan, Henrik A. Panosyan, Vache K. Gharibyan, Ani H. Hasratyan   +3 more
doaj   +1 more source

A Supramolecular Thermal Switch for Precision Pyroptosis via Host−Guest Recognition and Electrostatic Interactions

Advanced Science, EarlyView.
A supramolecular pyroptotic thermal switch encapsulates I3− within β‐cyclodextrin (β‐CD) and undergoes CaCO3 mineralization. Upon lysosomal acidification, CaCO3 is degraded, releasing Ca2+ and I3−. Concurrently, BODIPY activation converts I3− into I2, inducing oxidative stress and Ca2+ overload, which together trigger caspase‐3/GSDME‐mediated ...
Dan Wu, Jie Zhou, Yibin Cao, Kunmin Ping, Borui Zhao, Yanrong Yang, Chunyang Yu, Xinyang Yu, Shaolong Qi   +8 more
wiley   +1 more source

Heterogeneous Catalysts in Pictet-Spengler-Type Reactions

Journal of Chemistry, 2013
Several solid catalysts were evaluated as an alternative for 1,2,3,4-tetrahydroisoquinoline synthesis by means of the Pictet-Spengler reaction. The reaction catalysed by a mixed oxide (Mg and Al) led to the best yield and good regioselectivity; using an ...
Rodolfo Quevedo, Camilo Perdomo, Sonia Moreno   +2 more
doaj   +1 more source

A Straightforward Selective Acylation of Phenols over ZSM-5 towards Making Paracetamol Precursors

Bulletin of Chemical Reaction Engineering & Catalysis, 2018
Commercially available ZSM-5 was minimally treated as the catalyst to selectively acylate phenols. The ZSM-5 was simply immersed in ammonium nitrate in order to fill the pores with Brönsted acid to concentrate the catalytic reactions inside the pores ...
Robby Roswanda, Alfhons Daniel Sirampun, Rino Rakhmata Mukti, Didin Mujahidin   +3 more
doaj   +1 more source