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1,562 results on '"Zhou, Qi‐Lin"'

202. Nickel(0)-Catalyzed Hydroarylation of Styrenes and 1,3-Dienes with Organoboron Compounds.

Author

Xiao, Li‐Jun, Cheng, Lei, Feng, Wei‐Min, Li, Mao‐Lin, Xie, Jian‐Hua, and Zhou, Qi‐Lin

Subjects
CATALYSIS, NICKEL, CATALYSTS, ADDITION reactions, ALKENES
Abstract

A Ni-catalyzed hydroarylation of styrenes and 1,3-dienes with organoboron compounds has been developed. The reaction offers a highly selective approach to diarylalkanes and allylarenes under redox-neutral conditions. In this hydroarylation reaction, a new strategy that uses the proton of methanol to generate the active catalyst species Ni−H was developed. The Ni-catalyzed hydroarylation, combined with a Ir-catalyzed C−H borylation, affords a very efficient and straightforward access to a retinoic acid receptor agonist. [ABSTRACT FROM AUTHOR]

Published
2018
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203. Chiral mercaptoaryl-oxazolines as ligands in enantioselective copper-catalyzed 1,4-additions of Grignard reagents to enones

Author

Zhou Qi-Lin and Andreas Pfaltz

Subjects
Cyclopentenone, chemistry.chemical_classification, Ketone, Organic Chemistry, Enantioselective synthesis, chemistry.chemical_element, Alkylation, Biochemistry, Combinatorial chemistry, Copper, Catalysis, chemistry.chemical_compound, chemistry, Reagent, Drug Discovery, Organic chemistry, Enantiomeric excess
Abstract

A series of chiral enantiomerically pure mercaptoaryl-oxazolines has been synthesized. Copper(I) thiolate complexes derived from these ligands proved to be efficient catalysts for the 1,4-addition of Grignard reagents to cyclic enones. Enantioselectivities increased in the sequence cyclopentenone (16–37% ee)

Published
1994

204. The Stereochemistry of the Trinaphthyl‐Terrylene Conversion

Author

Manfred Wagner, Klaus Müllen, Martin Adam, Zhou Qi‐Lin, and Ute Anton

Subjects
Inorganic Chemistry, chemistry.chemical_classification, Steric effects, chemistry.chemical_compound, Polycyclic compound, chemistry, Stereochemistry, X-ray crystallography, Molecule, Reactivity (chemistry), Crystal structure, Alkylation, Naphthalene
Abstract

Alkylated terrylenes can be synthesized by a twofold cyclization of an appropriately substituted trinaphthyl[1, 11]. In this paper, we consider a special case. The alkyl substitution in the starting material 1 strongly affects the interplanar angle between the naphthalene moieties. After cyclization, the substituents are positioned in the sterically crowded bay region of the title structure 2. The influence of the steric strain on the reactivity of 1 and on the stability of the resulting hydrocarbon 2 is investigated. Special emphasis is placed on the crystal structures of 1 and 2.

Published
1993

238. Rhodium-Catalyzed B–H Bond Insertion Reactions of Unstabilized Diazo Compounds Generated in Situfrom Tosylhydrazones

Author

Pang, Yue, He, Qiao, Li, Zi-Qi, Yang, Ji-Min, Yu, Jin-Han, Zhu, Shou-Fei, and Zhou, Qi-Lin

Abstract

Although transition-metal-catalyzed B–H bond insertion of carbenes into stable borane adducts has emerged as a promising method for organoborane synthesis, all the diazo compounds used to date as carbene precursors have had an electron-withdrawing group to stabilize them. Herein, we report a protocol for rhodium-catalyzed B–H bond insertion reactions of unstabilized diazo compounds generated in situfrom tosylhydrazones. In addition, by using chiral dirhodium catalysts, we also achieved an asymmetric version of the reaction with good to excellent enantioselectivities (up to 98:2 e.r.). This is the first enantioselective heteroatom–hydrogen bond insertion reaction to use unstabilized diazo compounds as carbene precursors. The protocol exhibited good functional group tolerance and could be carried out on a gram scale. It also enabled one-pot transformation of a carbonyl group to a boryl group enantioselectively. The B–H bond insertion products could be easily transformed into chiral alcohols and other widely used organoboron reagents with enantiomeric fidelity.

Published
2018
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243. Magical Chiral Spiro Ligands

Author

Zhou Qi-Lin and Xie Jian-Hua

Subjects
Chemistry, Enantioselective synthesis, General Chemistry, Metal catalyst, Combinatorial chemistry
Published
2014

244. Front Cover Picture: Special Issue Dedicated to Andreas Pfaltz (Adv. Synth. Catal. 19/2022).

Author

Glorius, Frank and Zhou, Qi‐Lin

Subjects
*COLLEGE teachers
Abstract

The B front cover picture b shows examples of work developed by Professor Andreas Pfaltz, to whom this special issue of I Advanced Synthesis & Catalysis i is dedicated. For details see the commentary by the Issue Editors, Frank Glorius and Qi-Lin Zhou (F. Glorius, Q.-L. Front Cover Picture: Special Issue Dedicated to Andreas Pfaltz (Adv. [Extracted from the article]

Published
2022
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245. Optimization of enantiocontrol for carbon-hydrogen insertion with chiral dirhodium(II) carboxamidates: synthesis of natural dibenzylbutyrolactone lignans from 3-aryl-1-propyl diazoacetates in high optical purity

Author

Doyle, Michael P., Protopopova, Marina N., Zhou, Qi-Lin, Bode, Jeffrey W., Simonsen, Stanley H., and Lynch, Vincent

Subjects
Rhodium -- Usage, Lactones -- Analysis, Organic compounds -- Synthesis, Biological sciences, Chemistry
Abstract

A new, efficient carbon-hydrogen insertion methodology is used for the highly enantio- and regioselective syntheses of natural dibenzylbutyrolactone lignans from 3-aryl-1-propyl diazoacetates using chiral oxoimidazolidine carboxylate-ligated dirhodium(II) catalysts. The dirhodium catalysts are prepared from m-1-(3-phenylpropanoyl)-2-oxoimidazolidine-4(S)-carboxylate and its 4(R) enantiomer. The openness in the area around the rhodium catalyst, Rh2(4-R-MPPIM)4 allows insertion of the C-H bond.

Published
1995

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