نتایج جستجو برای: substutuent effect claisen rearrangement

تعداد نتایج: 1667083  

2012
Stefanie A. Sydlik Timothy M. Swager

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Current research in materials has devoted much attention to graphene, with a considerable amount of the chemical manipulation going through the oxidized state of the material, known as graphene oxide (GO). In this report, the hydroxyl functionalities in GO, the vast majority th...

2005
Jeremy R. Knowles

Stereoselectively labeled samples of E—2an Z—[9—2H,3H]— chorismate have been synthesized from Fand z-[3H, Hlphosphoen6lpyruvate by the enzymes of the shikimate pathway. The position of the tritium label at the 9—position of chorismate has been determined, from which it is evident that in the reaction catalyzed by 3-phosphoshikimate 1—carboxyvinyltransferase, the addition step has the opposite s...

2017
Daniel Burschowsky Ute Krengel Einar Uggerud David Balcells

Chorismate mutase is a well-known model enzyme, catalyzing the Claisen rearrangement of chorismate to prephenate. Recent high-resolution crystal structures along the reaction coordinate of this enzyme enabled computational analyses at unprecedented detail. Using quantum chemical simulations, we investigated how the catalytic reaction mechanism is affected by electrostatic and hydrogen-bond inte...

Journal: :Molecules 2018
Yoshihide Usami Aoi Kohno Hiroki Yoneyama Shinya Harusawa

Synthesis of novel pyrazole-fused heterocycles, i.e., dihydro-1H- or 2H-oxepino[3,2-c]pyrazoles (6 or 7) from 4-allyloxy-1H-pyrazoles (1) via combination of Claisen rearrangement and ring-closing metathesis (RCM) has been achieved. A suitable catalyst for the RCM of 5-allyl-4-allyloxy-1H-pyrazoles (4) was proved to be the Grubbs second generation catalyst (Grubbs2nd) to give the predicted RCM p...

2009
Julia Rehbein Markus Schürmann Hans Preut Martin Hiersemann

In the title compound, [Cu(C(17)H(30)N(2)O(2))(C(3)H(7)NO)(2)][SbF(6)](2), which is a potential catalyst in the asymmetric Gosteli-Claisen rearrangement, the Cu atom adopts a distorted cis-CuN(2)O(2) square-planar geometry arising from N,N'-bidentate coordin-ation by the chiral ligand and two O-bonded dimethyl-formamide mol-ecules. Two short C-H⋯O contacts occur within the ligand and two weak i...

2010
H M Sampath Kumar Sipak Joyasawal B V S Reddy P Pawan Chakravarthy A D Krishna J S Yadav

Allylic and benzylic alcohols are converted into corresponding unsymmetrical ethers when reacted with various orthoesters in the presence of montmorillonite KSF at ambient temperature. A detailed study has been undertaken to examine the mechanism and generality of these reactions with regard to various acidic catalysts, which reveal interesting competitive reactions mainly O-acetylation, togeth...

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