نتایج جستجو برای: phenacyl isoquinolinium ylide

تعداد نتایج: 762  

Journal: :Chemical communications 2014
Lei Hu Olof Ramström

A dynamic azomethine ylide system was established using Sc(OTf)3 and Ag/Taniaphos as catalysts. The system was subsequently kinetically resolved in a tandem 1,3-dipolar cycloaddition process where the silver complex acted as both a reaction catalyst and an external selector, resulting in the formation of an exclusive pyrrolidine product in good yield and enantiopurity.

Journal: :Organic & biomolecular chemistry 2006
Raphaël Robiette Matteo Conza Varinder K Aggarwal

Diastereoselectivity in reactions of aryl-stabilised ammonium ylides are highly sensitive to the nature of the amine and the ylide substituent. DFT calculations are consistent with a mechanism in which reversibility in betaine formation [despite the high energy (and therefore instability) of ammonium ylides] is finely balanced due to the high barrier to ring closure.

2012
R. S. Tewari A. K. Awasthi S. C. Chaturvedi

4-Nitrobenzylidenedimethylsulfurane 4-Nitrobenzylidenedimethylsulfurane, a semi-stabilized sulfonium ylide has been generated by the attack of methylsulfinyl carbanion in dimethyl sulfoxide and reacted with a series of substituted benzaldehydes, furfural and benzylideneacetophenone to afford <mns-l,2-disubstituted epoxides in fair to good yields. The structural assignments of the products are b...

Journal: :Chemical communications 2006
Mitsuo Komatsu Yukihiro Kasano Jin-ichi Yonemori Yoji Oderaotoshi Satoshi Minakata

Generation and cycloaddition of less- or non-stabilized azomethine ylides, or nitrile ylide equivalents, via unprecedented 1,4-stannatropy of N-(tributylstannylmethyl)thioamides were achieved. The reactions with dipolarophiles, such as electron-deficient alkenes and alkynes, afforded corresponding pyrrolidine and pyrrole derivatives effectively.

Journal: :Organic letters 2014
J Stephen Clark Laetitia Delion Louis J Farrugia

The synthesis of the compound that has been proposed to be the natural product sclerophytin F has been completed from a known vinylogous carbonate. The synthetic strategy relied upon rearrangement of a catalytically generated ylide-like intermediate to produce an oxabicyclo[6.2.1]-5-undecen-9-one and an intermolecular Diels-Alder reaction to construct the complete tricyclic core found in the na...

2012
Stefan Weigand

Lithiation of 1,2-dichloroor 1,2,3-trichloroferrocene with lithium tetramethylpiperidinide, followed by transmetallation with ZnCl2 and Pd(II)-catalyzed coupling with 2-bromopyridine, yield the pyridylferrocenes [CpFe{C5H2−nCl2+n(2-C5H4N)}] (2a, b, n = 0 or 1) as brown oils of low stability. Recrystallization of 2b produced a small number of X-ray quality crystals, which could be shown to have ...

Journal: :Angewandte Chemie 2003
Varinder K Aggarwal Imhyuck Bae Hee-Yoon Lee Jeffery Richardson David T Williams

2015
Diego M Andrada Nicole Holzmann Thomas Hamadi Gernot Frenking

Fifteen cyclic and acylic carbenes have been calculated with density functional theory at the BP86/def2-TZVPP level. The strength of the internal X→p(π) π-donation of heteroatoms and carbon which are bonded to the C(II) atom is estimated with the help of NBO calculations and with an energy decomposition analysis. The investigated molecules include N-heterocyclic carbenes (NHCs), the cyclic alky...

Journal: :Organic letters 2013
Brett R Ambler Ryan A Altman

The development of new synthetic fluorination reactions has important implications in medicinal, agricultural, and materials chemistries. Given the prevalence and accessibility of alcohols, methods to convert alcohols to trifluoromethanes are desirable. However, this transformation typically requires four-step processes, specialty chemicals, and/or stoichiometric metals to access the trifluorom...

2011
Dong Xing Dan Yang

A highly efficient gold(I)-catalyzed Overman rearrangement of allylic trichloroacetimidates to allylic trichloroacetamides in water is reported. With this environmentally benign and scalable protocol, a series of C3-alkyl substituted allylic trichloroacetamides were synthesized in good to high yields.

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