نتایج جستجو برای: substutuent effect claisen rearrangement

تعداد نتایج: 1667083  

Journal: :Bulletin of the Chemical Society of Japan 1984

2014
Hanna Bruss Hannah Schuster Rémi Martinez Markus Kaiser Andrey P Antonchick Herbert Waldmann

Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland-Claisen rearrangement can be employed to construct the central C9-C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the develo...

Journal: :Angewandte Chemie 2015
Hongmiao Wu Weiwei Zi Guigen Li Hongjian Lu F Dean Toste

An enantioselective alkoxylation/Claisen rearrangement reaction was achieved by a strategic desymmetrization of 1,4-dienes under the catalysis of (S)-DTBM-Segphos(AuCl)2/AgBF4. This reaction system was highly selective for the formation of 3,3-rearrangement products, providing cycloheptenes with various substitutions in good yield and good to excellent enantioselectivity. This transformation wa...

2017
Jun Zhang Zhen Zhang Yi Isaac Yang Sirui Liu Lijiang Yang Yi Qin Gao

Efficient sampling in both configuration and trajectory spaces, combined with mechanism analyses via data mining, allows a systematic investigation of the thermodynamics, kinetics, and molecular-detailed dynamics of chemical reactions in solution. Through a Bayesian learning algorithm, the reaction coordinate(s) of a (retro-)Claisen rearrangement in bulk water was variationally optimized. The b...

2014
Matthew F. L. Parker Sílvia Osuna Guillaume Bollot Shivaiah Vaddypally Michael J. Zdilla K. N. Houk Christian E. Schafmeister

A series of hydrogen-bonding catalysts have been designed for the aromatic Claisen rearrangement of a 1,1-dimethylallyl coumarin. These catalysts were designed as mimics of the two-point hydrogen-bonding interaction present in ketosteroid isomerase that has been proposed to stabilize a developing negative charge on the ether oxygen in the migration of the double bond.1 Two hydrogen bond donatin...

Journal: :Chemical communications 2013
John M Ketcham Berenger Biannic Aaron Aponick

The Au(I)-catalyzed intermolecular hydroalkoxylation of alkynes with allylic alcohols to provide allyl vinyl ethers that subsequently undergo Claisen rearrangement is reported. This new cascade reaction strategy facilitates the direct formation of γ,δ-unsaturated ketones from simple starting materials in a single step.

Journal: :Journal of the American Chemical Society 2004
Benjamin D Sherry F Dean Toste

Homoallenic alcohols are prepared from propargyl vinyl ethers using a trinuclear gold(I)-oxo complex, [(Ph3PAu)3O]BF4, as a catalyst for propargyl Claisen rearrangement at room temperature. The gold(I)-catalyzed reaction is effective for a diverse collection of propargyl vinyl ethers, including substrates containing aryl and alkyl groups at the propargylic position, and hydrogen, aryl, and alky...

Journal: :Organic & biomolecular chemistry 2009
Stephen G Davies A Christopher Garner Rebecca L Nicholson James Osborne Paul M Roberts Edward D Savory Andrew D Smith James E Thomson

The doubly diastereoselective [3,3]-sigmatropic aza-Claisen rearrangement of silylketene aminals derived from 5-substituted (3S,4E,alphaR)-1-benzyloxy-3-[N-acyl-N-(alpha-methylbenzyl)amino]pent-4-enes furnishes 2,3-disubstituted (R)-N-alpha-methylbenzyl (2S,3R,4E)-7-benzyloxyhept-4-enamides in >90% de under the "matched" control of both stereogenic centres. Rearrangement of the "mismatched" dia...

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