TEMPO-mediated homocoupling of aryl Grignard reagents: mechanistic studies

2015 ◽  
Vol 13 (9) ◽  
pp. 2762-2767 ◽  
Author(s):  
Sandip Murarka ◽  
Juri Möbus ◽  
Gerhard Erker ◽  
Christian Mück-Lichtenfeld ◽  
Armido Studer
Keyword(s):  
Grignard Reagents ◽  
Computational Studies ◽  
Mechanistic Studies

The mechanism of TEMPO mediated oxidative homo-coupling of aryl Grignard reagents to biphenyls is investigated in detail by experimental and computational studies.

Design and Development of Fe-Catalyzed Intra- and Intermolecular Carbofunctionalization of Vinyl Cyclopropanes

2019 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Mingbin Yuan ◽  
Chris Acha ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Bond Formation ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Mechanistic Studies ◽  
Radical Intermediates ◽  
Design And Implementation ◽  
Solvent Cage ◽  
Radical Cascade ◽  
Radical Processes

Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.

Recent Computational Studies on Mechanisms of Hypervalent Iodine(III)-Promoted Dearomatization of Phenols

2020 ◽  
Vol 24 (18) ◽  
pp. 2106-2117
Author(s):  
Hanliang Zheng ◽  
Xiao-Song Xue
Keyword(s):  
Hypervalent Iodine ◽  
Computational Studies ◽  
Mechanistic Studies

Hypervalent iodine-promoted dearomatization of phenols has received intense attention. This mini-review summarizes recent computational mechanistic studies of phenolic dearomatizations promoted by hypervalent iodine(III) reagents or catalysts. The first part of this review describes mechanisms of racemic dearomatization of phenols, paying special attention to the associative and dissociative pathways. The second part focuses on mechanisms and selectivities of diastereo- or enantio-selective dearomatization of phenols.

scholarly journals Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

2013 ◽  
Vol 9 ◽  
pp. 1472-1479 ◽  
Author(s):  
Brian M Casey ◽  
Dhandapani V Sadasivam ◽  
Robert A Flowers II
Keyword(s):  
Intramolecular Cyclization ◽  
Computational Studies ◽  
Mechanistic Studies ◽  
Dicarbonyl Compounds ◽  
Radical Intermediates ◽  
Aromatic Substrates ◽  
Site Selectivity ◽  
Intramolecular Cyclizations ◽  
Cyclohexadienyl Radical ◽  
The Stability

The synthesis of 2-tetralones through the cyclization of δ-aryl-β-dicarbonyl substrates by using CAN is described. Appropriately functionalized aromatic substrates undergo intramolecular cyclizations generating 2-tetralone derivatives in moderate to good yields. DFT computational studies indicate that successful formation of 2-tetralones from δ-aryl-β-dicarbonyl radicals is dependent on the stability of the subsequent cyclohexadienyl radical intermediates. Furthermore, DFT computational studies were used to rationalize the observed site selectivity in the 2-tetralone products.

Synthesis of quinolines and acridines by the reaction of 2-(perfluoroalkyl)anilines with lithium and Grignard reagents

2015 ◽  
Vol 21 (3) ◽  
pp. 145-151 ◽  
Author(s):  
Lucjan Strekowski ◽  
Jianguo Zhang ◽  
Jarosław Sączewski ◽  
Ewa Wolińska
Keyword(s):  
Grignard Reagents ◽  
Mechanistic Studies

AbstractThis review summarizes the synthesis of quinolines and acridines by the reactions of anionically activated 2-(perfluoroalkyl)anilines. Mechanistic studies including isolation of the intermediate aza-ortho-xylylene are discussed.

Mechanistic studies on the reaction of nitro- and nitrosoarenes with vinyl Grignard reagents

1991 ◽  
pp. 657 ◽  
Author(s):  
Marcella Bosco ◽  
Renato Dalpozzo ◽  
Giuseppe Bartoli ◽  
Gianni Palmieri ◽  
Marino Petrini
Keyword(s):  
Grignard Reagents ◽  
Mechanistic Studies

Design and Development of Fe-Catalyzed Intra- and Intermolecular Carbofunctionalization of Vinyl Cyclopropanes

2019 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Mingbin Yuan ◽  
Chris Acha ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Bond Formation ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Mechanistic Studies ◽  
Radical Intermediates ◽  
Design And Implementation ◽  
Solvent Cage ◽  
Radical Cascade ◽  
Radical Processes

Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.

scholarly journals Teaching an old carbocation new tricks: Intermolecular C–H insertion reactions of vinyl cations

Science ◽  
2018 ◽  
Vol 361 (6400) ◽  
pp. 381-387 ◽  
Author(s):  
Stasik Popov ◽  
Brian Shao ◽  
Alex L. Bagdasarian ◽  
Tyler R. Benton ◽  
Luyi Zou ◽  
...  
Keyword(s):  
Theoretical Studies ◽  
Computational Studies ◽  
Mechanistic Studies ◽  
Insertion Reactions ◽  
Bond Forming ◽  
The Past ◽  
Carbon Carbon Bond ◽  
Transition Structures ◽  
The Subject ◽  
Experimental And Theoretical Studies

Vinyl carbocations have been the subject of extensive experimental and theoretical studies over the past five decades. Despite this long history in chemistry, the utility of vinyl cations in chemical synthesis has been limited, with most reactivity studies focusing on solvolysis reactions or intramolecular processes. Here we report synthetic and mechanistic studies of vinyl cations generated through silylium–weakly coordinating anion catalysis. We find that these reactive intermediates undergo mild intermolecular carbon-carbon bond–forming reactions, including carbon-hydrogen (C–H) insertion into unactivated sp3 C–H bonds and reductive Friedel-Crafts reactions with arenes. Moreover, we conducted computational studies of these alkane C–H functionalization reactions and discovered that they proceed through nonclassical, ambimodal transition structures. This reaction manifold provides a framework for the catalytic functionalization of hydrocarbons using simple ketone derivatives.

Designing Rh(I)-Half-Sandwich Catalysts for Alkyne [2+2+2] Cycloadditions

Synlett ◽  
2020 ◽  
Author(s):  
Laura Orian ◽  
F. Matthias Bickelhaupt
Keyword(s):  
Rational Design ◽  
Computational Studies ◽  
Synthetic Route ◽  
Mechanistic Studies ◽  
Mild Conditions ◽  
Aromatic Ligand ◽  
Polycyclic Aromatic ◽  
Metal Catalyzed ◽  
Cyclopentadienyl Anion ◽  
Half Sandwich

AbstractMetal-mediated [2+2+2] cycloadditions of unsaturated molecules to cyclic and polycyclic organic compounds are a versatile synthetic route affording good yields and selectivity under mild conditions. In the last two decades, in silico investigations have unveiled important details about the mechanism and the energetics of the whole catalytic cycle. Particularly, a number of computational studies address the topic of half-sandwich catalysts which, due to their structural fluxionality, have been widely employed, since the 1980s. In these organometallic species, the metal is coordinated to an aromatic ring, typically the ubiquitous cyclopentadienyl anion, C5H5 –(Cp) or to the Cp moiety of a larger polycyclic aromatic ligand (Cp′). During the catalytic process, the metal continuously ‘slips’ on the ring, changing its hapticity. This phenomenon of metal slippage and its implications for the catalyst’s performance are discussed in this work, referring to the most important computational mechanistic studies reported in literature for Rh(I) half-metallocenes, with the purpose of providing hints for a rational design of this class of compounds.1 Introduction2 Mechanism of Metal-Catalyzed Acetylene [2+2+2] Cycloaddition to Benzene and the Problem of the Indenyl Effect2.1 Acetylene-Acetonitrile [2+2+2] Co-cycloaddition to 2-Methylpyridine: Evidence of the Indenyl Effect2.2 Heteroaromatic Catalysts and the Evidence of a Reverse Indenyl Effect2.3 Booth’s Mechanistic Hypothesis and the Evidence of the Indenyl Effect3 Structure–Reactivity Correlation: The Slippage-Span Model4 Conclusions and Perspectives

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