- The intramolecular reaction of acetophenoneN-tosylhydrazone and vinyl: Br?nsted acid-promoted cationic cyclization toward polysubstituted indenes
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In the presence of TsNHNH2, a Br?nsted acid-promoted intramolecular cyclization ofo-(1-arylvinyl) acetophenone derivatives was developed, leading to polysubstituted indenes with complexity and diversity in moderate to excellent yields. In sharp contrast with either the radical or carbene involved cyclization of aldehydicN-tosylhydrazone with vinyl, a cationic cyclization pathway was involved, whereN-tosylhydrazone served as an electrophile and alkylation reagent during this transformation.
- Wang, Zhixin,Li, Yang,Chen, Fan,Qian, Peng-Cheng,Cheng, Jiang
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p. 1810 - 1813
(2021/02/27)
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- Synthesis of 1-indanols and 1-indanamines by intramolecular palladium(0)-catalyzed C(sp3)-H arylation: Impact of conformational effects
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A range of valuable 1-indanols and 1-indanamines containing a tertiary C1 atom were synthesized by intramolecular palladium(0)-catalyzed C(sp 3)-H arylation, despite unfavorable steric interactions. The efficiency of the reaction was found to correlate with the degree of substitution at C2, as expected from the Thorpe-Ingold effect. Additionally, the nature of the heteroatomic substituent at C1 had a marked influence on the diastereoselectivity at C1 and C2; indeed, 1-indanols and 1-indanamines were obtained with the opposite relative configuration. Analysis of the X-ray and DFT-optimized structures of the corresponding reactive intermediates provided useful insights into the subtle conformational effects induced by these substituents.
- Janody, Simon,Jazzar, Rodolphe,Comte, Arnaud,Holstein, Philipp M.,Baudoin, Olivier,Vors, Jean-Pierre,Ford, Mark J.
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supporting information
p. 11084 - 11090,7
(2014/10/15)
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- High-yielding, versatile, and practical [Rh(III)Cp*]-catalyzed ortho bromination and iodination of arenes
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We report a uniquely high-yielding, general, and practical ortho bromination and iodination reaction of different classes of aromatic compounds. This reaction occurs by Rh(III)-catalyzed C-H bond activation methodology and is therefore the first example of the application of this cationic catalyst for C-Br and C-I bond formation.
- Schroeder, Nils,Wencel-Delord, Joanna,Glorius, Frank
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supporting information; experimental part
p. 8298 - 8301
(2012/06/29)
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- Intramolecular palladium-catalyzed alkane C-H arylation from aryl chlorides
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The first examples of efficient and general palladium-catalyzed intramolecular C(sp3)-H arylation of (hetero)aryl chlorides, giving rise to a variety of valuable cyclobutarenes, indanes, indolines, dihydrobenzofurans, and indanones, are described. The use of aryl and heteroaryl chlorides significantly improves the scope of C(sp3)-H arylation by facilitating the preparation of reaction substrates. Careful optimization studies have shown that the palladium ligand and the base/solvent combination are crucial to obtaining the desired class of product in high yields. Overall, three sets of reaction conditions employing PtBu3, PCyp3, or PCy3 as the palladium ligand and K 2CO3/DMF or Cs2CO3/pivalic acid/mesitylene as the base/solvent combination allowed five different classes of products to be accessed using this methodology. In total, more than 40 examples of C-H arylation have been performed successfully. When several types of C(sp3)-H bond were present in the substrate, the arylation was found to occur regioselectively at primary C-H bonds vs secondary or tertiary positions. In addition, in the presence of several primary C-H bonds, selectivity trends correlate with the size of the palladacyclic intermediate, with five-membered rings being favored over six- and seven-membered rings. Regio- and diastereoselectivity issues were studied computationally in the prototypal case of indane formation. DFT(B3PW91) calculations demonstrated that C-H activation is the rate-determining step and that the creation of a C-H agostic interaction, increasing the acidity of a geminal C-H bond, is a critical factor for the regiochemistry control.
- Rousseaux, Sophie,Davi, Michael,Sofack-Kreutzer, Julien,Pierre, Cathleen,Kefalidis, Christos E.,Clot, Eric,Fagnou, Keith,Baudoin, Olivier
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supporting information; experimental part
p. 10706 - 10716
(2010/09/17)
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- Unexpected cross-coupling reaction between o-chloroaryl ketones and organomanganese reagents
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(Chemical equation presented) Alkyl- and arylmanganese reagents react with o-chloro or o-bromoaryl ketones to give the substituted ketones in high yields. The cross-coupling reaction is performed under mild conditions (-60 to +40°C, 30 min to 4 h) and tak
- Cahiez, Gerard,Luart, Denis,Lecomte, Fabien
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p. 4395 - 4398
(2007/10/03)
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- Synthesis of novel optically active tin hydrides containing chiral ligands
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The synthesis of the chiral tin bromides 1-4 and hydrides 5-8, containing the potentially bidentate, optically active 2[(lS/fl)-l-dimethylaminoethyl]phenyl and 2-[(lS)-l-dimethylamino-2,2-dimethylpropyl]phenyl ligands, is reported. The tin hydrides 5-8, w
- Schwarzkopf, Kay,Metzger, Juergen O.,Saak, Wolfgang,Ponl, Siegfried
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p. 1539 - 1546
(2007/10/03)
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- Facile synthesis of pivalophenones by an ultrasound assisted iodine catalysed Friedel-Crafts acylation reaction
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The use of ultrasound in the acylation reactions of various aromatics and heterocyclics with pivaloyl chloride in the presence of catalytic amount of iodine, without any added solvent and at room temperature, gives excellent yields of the respective pivalophenones in a short reaction time.
- Gopalakrishnan, Geetha,Anandhi,Narasimhan
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p. 1197 - 1198
(2007/10/03)
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- A facile synthesis of pivalophenones by ultrasound assisted AlCl3 catalysed Friedel-Crafts reaction
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Pivalophenones have been prepared by the acylation reaction of various aromatic and heterocyclic compounds with pivaloyl chloride using AlCl3 as catalyst under sonochemical conditions in a short reaction time and in reasonable yields.
- Gopalakrishnan, Geetha,Anandhi,Narasimhan
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p. 1194 - 1196
(2007/10/03)
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