108-68-9Relevant articles and documents
Monitoring of the Phosphine Role in the Mechanism of Palladium-Catalyzed Benzosilole Formation from Aryloxyethynyl Silanes
Gimferrer, Martí,Minami, Yasunori,Noguchi, Yuta,Hiyama, Tamejiro,Poater, Albert
, p. 1456 - 1461 (2018)
Understanding the formation of benzosiloles by the intramolecular palladium-catalyzed annulation of alkynyl(aryl)silanes is crucial for achieving synthetic diversity toward the enhancement of the chemistry of siloles. By a combination of density functional theory calculations and experiments, we describe not only the whole mechanism of reaction but also the drawbacks that block this type of reaction. We also unravel the role of the phosphine ligand, without which the reactions could not go forward. Moreover, in silico predictive catalysis is presented here since the substitution of the phosphine ligand by an N-heterocyclic carbene (NHC) promises milder experimental conditions. A screening of substrates with different electronic properties was carried out to further understand the two fundamental steps of the reaction: stereoisomerization and concerted metalation-deprotonation.
Directional molecular transportation based on a catalytic stopper-leaving rotaxane system
Meng, Zheng,Xiang, Jun-Feng,Chen, Chuan-Feng
, p. 5652 - 5658 (2016)
Ratchet mechanism has proved to be a key principle in designing molecular motors and machines that exploit random thermal fluctuations for directional motion with energy input. To integrate ratchet mechanism into artificial systems, precise molecular design is a prerequisite to control the pathway of relative motion between their subcomponents, which is still a formidable challenge. Herein, we report a straightforward method to control the transportation barrier of a macrocycle by selectively detaching one of the two stoppers using a novel DBU-catalyzed stopperleaving reaction in a rotaxane system. The macrocycle was first allowed to thread onto a semidumbbell axle from the open end and subsequently thermodynamically captured into a nonsymmetrical rotaxane. Then, it was driven energetically uphill until it reached a kinetically trapped state by destroying its interaction with ammonium site, and was finally quantitatively released from the other end when the corresponding stopper barrier was removed. Although the directional transportation at the present system was achieved by discrete chemical reactions for the sake of higher transportation efficiency, it represents a new molecular transportation model by the strategy of using stopper-leavable rotaxane.
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de Mayo,P.,Takeshita,H.
, p. 440 - 449 (1963)
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Decarboxylative Hydroxylation of Benzoic Acids
Ritter, Tobias,Su, Wanqi,Xu, Peng
, p. 24012 - 24017 (2021/10/06)
Herein, we report the first decarboxylative hydroxylation to synthesize phenols from benzoic acids at 35 °C via photoinduced ligand-to-metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation. The aromatic decarboxylative hydroxylation is synthetically promising due to its mild conditions, broad substrate scope, and late-stage applications.
Reaction of hydroxyl radical with arenes in solution—On the importance of benzylic hydrogen abstraction
Waggoner, Abygail R.,Abdulrahman, Yahya,Iverson, Alexis J.,Gibson, Ethan P.,Buckles, Mark A.,Poole, James S.
, (2021/08/27)
The regioselectivity of hydroxyl radical reactions with alkylarenes was investigated using a nuclear magnetic resonance (NMR)-based methodology capable of trapping and quantifying addition and hydrogen abstraction products of the initial elementary step of the oxidation process. Abstraction products are relatively minor components of the product mixtures (15–30 mol%), depending on the magnitude of the overall rate coefficient and the number of available hydrogens. The relative reactivity of addition at a given position on the ring depends on its relation to the methyl substituents on the hydrocarbons under study. The reactivity enhancements for disubstituted and trisubstituted rings are approximately additive under the conditions of this study.