نتایج جستجو برای: phosphorus ylide

تعداد نتایج: 41924  

Journal: :Journal of the American Chemical Society 2013
Xueliang Huang Mahendra Patil Christophe Farès Walter Thiel Nuno Maulide

The development of a direct ylide transfer to carbonyl derivatives and of a sulfoxide-mediated arylation is presented from a unified perspective. Mechanistic studies (including density functional calculations) support a common reaction pathway and showcase how subtle changes in reactant properties can lead to disparate and seemingly unrelated reaction outcomes.

Journal: :The Journal of organic chemistry 2002
Xiaomei Zhang Zhaohui Qu Zhihua Ma Weifeng Shi Xianglin Jin Jianbo Wang

Catalytic asymmetric sulfur ylide [2,3]-sigmatropic rearrangement of carbenoids generated from aryldiazoacetates has been investigated with a number of chiral Rh(II) and Cu(I) catalysts, and moderately high enantioselectivity (52-78% ee) can be achieved with Cu(MeCN)(4)PF(6)/2,2'-isopropylidenebis[(4S)-4-tert-butyl-2-oxazoline].

Journal: :Chemical communications 2014
Mickaël Dos Santos Paul W Davies

An efficient C-O, C-S and C-C bond-forming sequence leads to functionalised compounds bearing sulfur-substituted quaternary carbons. Ynamides are employed as diazo-equivalents to access the [2,3]-sigmatropic rearrangements of allyl sulfonium ylides by a three-component chemoselective oxidation and intermolecular ylide formation.

Journal: :Organic & biomolecular chemistry 2014
Shaoyin Wang Xiancui Zhu Zhuo Chai Shaowu Wang

Polysubstituted pyrroles were regioselectively synthesized in moderate to good yields via the copper acetate-catalyzed [3 + 2] annulation reaction of readily accessible aziridines and nitroalkenes. This reaction was proposed to proceed through a key azomethine ylide intermediate generated by selective C-C bond cleavage of the aziridine followed by annulation with nitroalkenes under aerobic cond...

2015
Esma Lamera Abdelmalek Bouraiou Zouhair Bouaziz Aissa Chibani Norbert Haider

A novel compound, methyl 3-(quinolin-2-yl)indolizine-1-carboxylate (2) has been synthesized by cycloaddition reaction of 1-(quinolin-2-ylmethyl)pyridinium ylide (1) with methyl propiolate in presence of sodium hydride in THF. The structure of this compound was established by IR, 1H-NMR, 13C-NMR and MS data.

Journal: :Organic & biomolecular chemistry 2006
Marion Davoust Jean-François Brière Patrick Metzner

A highly diastereoselective organocatalytic synthesis of unique functionalised vinyl epoxides, displaying a Morita-Baylis-Hillman backbone, has been developed by means of an user friendly sulfonium ylide epoxidation of aldehydes from a readily available alpha-(bromomethyl)acrylamide derivative. The first result in the asymmetric version is discussed.

Journal: :Molecules 2017
Yi Li Qing-Zhu Li Li Huang Hong Liang Kai-Chuan Yang Hai-Jun Leng Yue Liu Xu-Dong Shen Xiao-Jun Gou Jun-Long Li

A highly diastereoselective cyclopropanation of cyclic enones with sulfur ylides was developed under catalyst-free conditions, producing multifunctional spirocyclopropanes in generally excellent yields (up to 99% yield and >99:1 d.r.). The asymmetric version of this method was realized by using an easily available chiral sulfur ylide, affording products with moderate to good stereoselectivity.

Journal: :Organic & biomolecular chemistry 2011
Andrew I Franklin David Bensa Harry Adams Iain Coldham

Intramolecular transannular dipolar cycloaddition was investigated as a key step in a synthetic approach to the core of the sarain alkaloids; although the use of an azomethine ylide was unsuccessful with the chosen aldehyde substrate, cycloaddition with a nitrone did give the alternative regioisomeric bridged cycloadduct.

Journal: :Chemistry 2006
Christian M Frech Olivier Blacque Helmut W Schmalle Heinz Berke Christian Adlhart Peter Chen

The reaction of [Re(H)(NO)2(PR3)2] complexes (1 a: R = PCy3; 1 b: R = PiPr3) with [H(OEt2)2][BAr(F)4] ([BAr(F)4] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) in benzene at room temperature gave the corresponding cations [Re(NO)2(PR3)2][BAr(F)4] (2 a and 2 b). The addition of phenyldiazomethane to benzene solutions of 2 a and 2 b afforded the moderately stable cationic rhenium(I)-benzyliden...

A highly efficient Ullmann homocoupling reaction of aryl halides using palladium (II) phosphine-ylide complexes as homogenous pre-catalysts under aerobic conditions has been developed without the need for any chemical co‐reducing agents. The procedure is relatively mild and appears to have broad applicability, being useful for the homocoupling of both electron-deficient and electron-rich aryl h...

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