نتایج جستجو برای: alkynes

تعداد نتایج: 3647  

Journal: :Organic letters 2009
Yining Ji Antoni Riera Xavier Verdaguer

The asymmetric intermolecular Pauson-Khand reaction of symmetric alkynes has been accomplished for the first time. N-Phosphino-p-tolylsulfinamide (PNSO) ligands have been identified as efficient ligands in this process. The chirality of the cobalt S-bonded sulfinyl moiety was found to direct olefin insertion into one of the two possible cobalt-carbon bonds in the alkyne complex. Reaction of sym...

Journal: :Organic letters 2012
Zhao Yuan Gui-Chao Kuang Ronald J Clark Lei Zhu

Unsymmetrical bisazides containing chelating and nonchelating azido groups undergo chemoselective three-component copper(I)-catalyzed azide-alkyne conjugation reactions with two different alkyne molecules. In conjunction with the reactivity gap between aromatic and aliphatic alkynes, a bistriazole molecule can be generated with excellent regioselectivity by mixing two alkynes and a bisazide in ...

2016
Melvyn B. Ansell Vitor H. Menezes da Silva Gabriel Heerdt Ataualpa A. C. Braga John Spencer Oscar Navarro

PdIJITMe)2(PhCCPh) acts as a highly reactive pre-catalyst in the unprecedented homogenous catalyzed diboration of terminal and internal alkynes, yielding a number of novel and known syn-1,2-diborylalkenes in a 100% stereoselective manner. DFT calculations suggest that a similar reaction pathway to that proposed for platinum phosphine analogues is followed, and that destabilization of key inter...

2015
Pavel K Mykhailiuk

A one-pot reaction between C2F5CH2NH2·HCl, NaNO2 and electron-deficient alkynes gives C2F5-substituted pyrazoles in excellent yields. The transformation smoothly proceeds in dichloromethane/water, tolerates the presence of air, and requires no purification of products by column chromatography. Mechanistically, C2F5CH2NH2·HCl and NaNO2 react first in water to generate C2F5CHN2, that participates...

2013
Morgane Gaydou Antonio M Echavarren

Cycloadditions of azides with alkynes to form triazoles under thermal conditions (Huisgen cycloaddition) or in the presence of copper [click reaction, copper-catalyzed azide– alkyne cycloaddition (CuAAC)] are reactions of fundamental importance in organic chemistry. Triazoles can also be obtained by means of ruthenium, silver, and iridium catalysis, as well as by a zinc-mediated process. In sha...

Journal: :Dalton transactions 2015
Bhausaheb Dhokale Thaksen Jadhav Shaikh M Mobin Rajneesh Misra

We report the synthesis of meso enyne substituted BODIPYs by the reaction of 8-chloro BODIPY with terminal alkynes under Sonogashira coupling conditions, and by Pd-Cu catalyzed hydroalkynylation reaction of terminal alkynes, across the -C[triple bond, length as m-dash]C- bond of meso alkynylated BODIPYs. The scope of reaction was explored by reacting different meso alkynylated BODIPYs with vari...

Journal: :Organic & biomolecular chemistry 2014
Shaoxia Lin Mengru Li Zhiyong Dong Fushun Liang Jingping Zhang

Hypervalent iodine(III)-mediated dioxygenation and diamination of alkenes have been previously developed. In this study, the potential application of hypervalent iodine(III) reagent was successfully extended to the dialkylation and cyclopropa(e)nation of unsaturated alkenes and alkynes. The reactions of alkenes with malononitrile and other active methylene compounds as the carbon nucleophiles g...

2005
Jack DeRuiter

Hydrocarbons are organic compounds consisting of C-C and C-H bonds. Carbon has a valence of four and thus requires four electrons or bonds to complete its octet in the neutral state. Hydrogen has a valence of one and thus requires a single electron or bond to complete its "duet" in the neutral state. Thus in hydrocarbons carbon can form neutral bonding arrangements by forming single bonds with ...

Journal: :Chemical Society reviews 2003
Frauke Pohlki Sven Doye

The direct addition of ammonia or primary and secondary amines to non-activated alkenes and alkynes is potentially the most efficient approach towards the synthesis of higher substituted nitrogen-containing products. It represents the most atom economic process for the formation of amines, enamines and imines, which are important bulk and fine chemicals or building blocks in organic synthesis. ...

Journal: :Journal of the American Chemical Society 2012
Mei Yan Tienan Jin Yoshifumi Ishikawa Taketoshi Minato Takeshi Fujita Lu-Yang Chen Ming Bao Naoki Asao Ming-Wei Chen Yoshinori Yamamoto

We report for the first time the highly selective semihydrogenation of alkynes using the unsupported nanoporous gold (AuNPore) as a catalyst and organosilanes with water as a hydrogen source. Under the optimized reaction conditions, the present semihydrogenation of various terminal- and internal-alkynes affords the corresponding alkenes in high chemical yields and excellent Z-selectivity withou...

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