Results 141 to 150 of about 39,817 (294)

Stereocontrol in Conformationally Stable C(sp2)─C(sp3) Atropisomers

Angewandte Chemie, EarlyView.
Building in our expertize in the synthesis of trans‐dihydrobenzofurans via organocatalyzed domino Michael/O‐cyclization between β‐naphthols and nitroalkenes, we developed an efficient strategy to access a new family of atropisomers bearing a conformationally stable C(sp2)─C(sp3) bond and two stereogenic centers through simple and highly ...
Antoine Domain, Guishun Bai, Juan‐Carlos Castillo, Hassane Moussa Abdraman, Stéphane Humbel, Michel Giorgi, Jean‐Valère Naubron, Sara Chentouf, Jean Rodriguez, Xiaoze Bao, Damien Bonne   +10 more
wiley   +2 more sources

Asymmetric Aziridination of Allylic Carbamates Using Ion‐Paired Rhodium Complexes and Extrapolation to C─H Amination of Phenethyl Carbamates

Angewandte Chemie, EarlyView.
Aziridination of alkenes is an important route to chiral nitrogen‐containing building blocks. We report that carbamate‐functionalized allylic alcohols undergo highly enantioselective aziridination using achiral dimeric Rh complexes ion‐paired with cinchona alkaloid‐derived chiral cations.
Arthur R. Lit, Shotaro Takano, Christian Zachau, Ioana Băltărețu, Robert J. Phipps   +4 more
wiley   +2 more sources

Research Progress on the Selectivity and Biomagnification of Chiral Hexabromocyclododecanes Pollutants in Food Chain Transfer

Yankuang ceshi, 2016
Hexabromocyclododecanes (HBCDs) are globally produced brominated flame retardant (BFR) and are used primarily as an additive FR in thermal insulation building materials, upholstery textiles, and electronics.
TIAN Qin, TONG Ling, SONG Shu-ling, ZHAN Nan, PAN Meng, QIU Jing   +5 more
doaj   +1 more source

Identification of Ti(salen) Complexes for Efficient Catalysis in Single‐Electron Steps by Cyclic Voltammetry

Angewandte Chemie, EarlyView.
Catalyst screening without catalysis. By combining cyclic voltammetry and DFT calculations we were able to identify a highly active catalyst for the radical arylation of epoxides without performing any reactions. The prevention of chloride binding that leads to catalyst inhibition was established as the key structural feature.
Niklas Schmickler, Sergei Gerber, Lennart Hanz, Stefan Grimme, Zheng‐Wang Qu, Inke Siewert, Andreas Gansäuer   +6 more
wiley   +2 more sources

Stereoselective bioaccumulation and degradation of chiral pesticide hexythiazox in earthworm-soil microcosm

Ecotoxicology and Environmental Safety
The chiral pesticide hexythiazox was extensively employed in agricultural activities and has garnered growing concern for its harmful impact on the ecosystem.
Ningying Song, Jiyang Zhuang, Hu Zhang, Mingrong Qian, Huizhen Wu, Nabo Sun   +5 more
doaj  

Asymmetric Intramolecular α‐Arylation of Polar Amino Acids Bearing β‐Leaving Groups

Angewandte Chemie, EarlyView.
Use of enolate chemistry to functionalise amino acids with β‐heteroatom side‐chains (serine, cysteine, threonine, etc.) is hampered by β‐elimination. We show that α‐arylation can be achieved by incorporating the side chain into a saturated heterocycle, making the unwanted elimination a disfavoured 5‐endo‐trig reaction.
Ömer Taspinar, Daniel J. Leonard, Nathan Picois, Cornelia Göcke, Matej Žabka, Hazel A. Sparkes, Jonathan Clayden   +6 more
wiley   +2 more sources

Copper-Catalyzed Asymmetric Carboboronation of Allenes to Access α-Quaternary Amino Esters with Adjacent Stereocenters

Cell Reports Physical Science, 2020
Summary: Optically active α-quaternary amino acids have received much attention because of the important biomedical applications implicated for compounds containing this structure.
Chao-Yang Zhao, Hao Zheng, Ding-Wei Ji, Xiang-Ting Min, Yan-Cheng Hu, Qing-An Chen   +5 more
doaj  

Shaping of a Reactive Manganese Catalyst Enables Access to Polyfunctionalized Cyclohexanes via Enantioselective C(sp3)─H Bond Oxidation of 1,3‐meso Diethers

Angewandte Chemie, EarlyView.
Structural shaping of a highly reactive chiral Mn‐oxo species translates into exceptionally enantioselective C─H oxidation catalyst of cyclohexyl 1,3‐meso diethers (up to >99% ee) leading to polyfunctionalized cyclohexanes. Abstract Chiral polyoxygenated cyclohexanes are valuable constituents of biologically relevant products.
Andrea Palone, Arnau Call, Aleria Garcia‐Roca, Josep M. Luis, Matthew S. Sigman, Massimo Bietti, Cristina Nevado, Miquel Costas   +7 more
wiley   +2 more sources

Rapid Access to an Enantioenriched Spiro Bisindole Directly from Indole and Acetone

Angewandte Chemie, EarlyView.
A catalytic enantioselective one‐pot “self‐assembly” strategy was developed for the exceedingly convenient access to a spiro bisindole directly from indole and acetone. The obtained enantiopure C2‐symmetric bisindole showed exceptional performance as a chiral backbone of diverse effective catalysts or ligands. Abstract Disclosed here is a “one‐pot self‐
Jing‐Yi Wang, Jie Lin, Chaoshen Zhang, Jianwei Sun   +3 more
wiley   +2 more sources

Catalytic enantioselective synthesis of quaternary carbon stereocentres. [PDF]

, 2014
Quaternary carbon stereocentres-carbon atoms to which four distinct carbon substituents are attached-are common features of molecules found in nature. However, before recent advances in chemical catalysis, there were few methods of constructing single ...
Overman, Larry E, Quasdorf, Kyle W
core