90221-55-9Relevant academic research and scientific papers
AuCl3-Catalyzed Ring-Closing Carbonyl–Olefin Metathesis
Wang, Rui,Chen, Yi,Shu, Mao,Zhao, Wenwen,Tao, Maoling,Du, Chao,Fu, Xiaoya,Li, Ao,Lin, Zhihua
supporting information, p. 1941 - 1946 (2020/02/11)
Compared with the ripeness of olefin metathesis, exploration of the construction of carbon–carbon double bonds through the catalytic carbonyl–olefin metathesis reaction remains stagnant and has received scant attention. Herein, a highly efficient AuCl3-catalyzed intramolecular ring-closing carbonyl–olefin metathesis reaction is described. This method features easily accessible starting materials, simple operation, good functional-group tolerance and short reaction times, and provides the target cyclopentenes, polycycles, benzocarbocycles, and N-heterocycle derivatives in good to excellent yields.
Palladium-Catalyzed Ring-Forming Aminoalkenylation of Alkenes with Aldehydes Initiated by Intramolecular Aminopalladation
Hu, Yue,Xie, Yinjun,Shen, Zhiqiang,Huang, Hanmin
, p. 2473 - 2477 (2017/02/23)
A palladium-catalyzed aminopalladation reaction followed by nucleophilic addition with aldehydes and dehydration is described. This direct and operationally simple procedure provides a rapid and reliable approach to a wide range of functionalized tetrahydroisoquinolines with high selectivity. Mechanistic studies disclosed that the nucleophilic addition, performed via a highly ordered transition-state, is the turnover-limiting step in which the inherent β-hydride elimination of the key Csp3?Pd species was controlled by the confined conformation and the nucleophilicity of the Csp3?Pd bond was enhanced by the strong electron-donating effect of the nitrogen atom.
Intriguing substituent effect in modified Hoveyda-Grubbs metathesis catalysts incorporating a chelating iodo-benzylidene ligand
Barbasiewicz, Michal,Blocki, Krzysztof,Malinska, Maura,Pawlowski, Robert
supporting information, p. 355 - 358 (2013/02/22)
A series of modified Hoveyda-Grubbs catalysts incorporating a chelating iodo-benzylidene ligand were prepared and characterized. The presence of electron-withdrawing ring substituents in the para position to the iodide was found to decrease the catalytic activity, revealing that dissociation of the Ru...I-Ar bond is not the rate-determining step.
Hydrogen-bonding catalysis and inhibition by simple solvents in the stereoselective kinetic epoxide-opening spirocyclization of glycal epoxides to form spiroketals
Wurst, Jacqueline M.,Liu, Guodong,Tan, Derek S.
supporting information; experimental part, p. 7916 - 7925 (2011/07/08)
Mechanistic investigations of a MeOH-induced kinetic epoxide-opening spirocyclization of glycal epoxides have revealed dramatic, specific roles for simple solvents in hydrogen-bonding catalysis of this reaction to form spiroketal products stereoselectively with inversion of configuration at the anomeric carbon. A series of electronically tuned C1-aryl glycal epoxides was used to study the mechanism of this reaction based on differential reaction rates and inherent preferences for SN2 versus SN1 reaction manifolds. Hammett analysis of reaction kinetics with these substrates is consistent with an SN2 or SN2-like mechanism (ρ = -1.3 vs ρ = -5.1 for corresponding SN1 reactions of these substrates). Notably, the spirocyclization reaction is second-order dependent on MeOH, and the glycal ring oxygen is required for second-order MeOH catalysis. However, acetone cosolvent is a first-order inhibitor of the reaction. A transition state consistent with the experimental data is proposed in which one equivalent of MeOH activates the epoxide electrophile via a hydrogen bond while a second equivalent of MeOH chelates the side-chain nucleophile and glycal ring oxygen. A paradoxical previous observation that decreased MeOH concentration leads to increased competing intermolecular methyl glycoside formation is resolved by the finding that this side reaction is only first-order dependent on MeOH. This study highlights the unusual abilities of simple solvents to act as hydrogen-bonding catalysts and inhibitors in epoxide-opening reactions, providing both stereoselectivity and discrimination between competing reaction manifolds. This spirocyclization reaction provides efficient, stereocontrolled access to spiroketals that are key structural motifs in natural products.
DIAMINOPROPANE DERIVED MACROCYCLES AS INHIBITORS OF BETA AMYLOID PRODUCTION
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Page/Page column 31, (2008/12/07)
There is provided a series of macrocyclic diaminopropanes of Formula (I) or a stereoisomer; or a pharmaceutically acceptable salt thereof, wherein R1, R2, R3, m, n, W, X, Y, Z and L as defined herein, their pharmaceutical compositions and methods of use. These novel compounds inhibit the processing of amyloid precursor protein (APP) by β-secretase and, more specifically, inhibit the production of Aβ-peptide. The present disclosure is directed to compounds useful in the treatment of neurological disorders related to β-amyloid production, such as Alzheimer's disease and other conditions affected by anti-amyloid activity.
