1,721,077 research outputs found
The conversion of vinyl triflates into γ'-hydroxy-α,β-enones
No full textVinyl triflates have been converted into γ'-hydroxy-α,β-enones through their palladium-catalysed coupling with 1-butyn-4-ols followed by the reaction of the obtained 1-hydroxy-3-yn-5-enes in an acidic CH2Cl2/3 N HCl two-phase system in the presence of the n-BuN4Cl/PdCl2 combination. Both the coupling step and the conversion of the carbon-carbon triple bond into the ketonic group have been performed at room temperature. The conversion of vinyl triflates into γ'-hydroxy-α,β-enones can be carried out through a one-flask process, without the isolation of 1-hydroxy-3-yn-5-enes
Synthesis of Nitrogen-Containing Heterocyclic Scaffolds through Sequential Reactions of Aminoalkynes with Carbonyls
Full text linkSequential reactions of aminoalkynes represent a powerful tool to easily assembly biologically important polyfunctionalized nitrogen heterocyclic scaffolds. Metal catalysis often plays a key role in terms of selectivity, efficiency, atom economy, and green chemistry of these sequential approaches. This review examines the existing literature on the applications of reactions of aminoalkynes with carbonyls, which are emerging for their synthetic potential. Aspects concerning the features of the starting reagents, the catalytic systems, alternative reaction conditions, pathways and possible intermediates are provided
PALLADIUM-CATALYZED REDUCTIVE ADDITION OF ARYL IODIDES TO ARYL AND ALKYLETHYNYLSILANES - A STEREO AND REGIOSELECTIVE ROUTE TO FUNCTIONALIZED 2,2-DISUBSTITUTED VINYLSILANES
No full textThe palladuim-catalyzed addition to carbon-carbon multiple bonds as a tool for the synthesis of heterocyclic derivatives
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Friedländer-Type Reaction of 4-Cholesten-3-one with 2′-Aminoacetophenone: Angular versus Linear Quinoline-Fused Steroids
Full text linkTo optimize the experimental conditions used for the Friedländer-type condensation, an angular fused 4-substituted quinoline steroid has been obtained in very high yield and regioselectivity using readily available 4-cholesten-3-one and 2′-aminoacetophenone. Moreover, by varying the reaction conditions and the catalyst, the corresponding linear regioisomer was also achieved with an acceptable isolated yield and high chemoselectivity. Both structures have been definitively elucidated via 2D-NMR and fully characterized
Synthesis of Indole Derivatives from 2-Alkynylanilines by Means of Gold Catalysis
No full textThe peculiar features of gold(III) and gold(I) species include exceptional carbophilicity and, at the same time, lone pair affinity. Such a combination offers many advantages for the development of more sustainable approaches to the synthesis of indole derivatives from readily available 2-alkynylanilines. This mini-review critically summarizes the literature reports in this field, with the aim to encourage further research activities in this promising area
The reaction of Meldrum's acid derivatives with conjugated azoalkenes: a convenient route to 1-amino-1H-pyrrol-2(3H)-ones
No full textTHE PALLADIUM-CATALYZED CARBONYLATIVE COUPLING OF 5-(TRIMETHYLSILYLETHYNYL)-3',5'-DI-O-ACETYL-2' DEOXYURIDINE AND 1-ALKYNES WITH ARYL IODIDES
No full textThe palladium-catalysed reaction of 5(trimethylsilylethynyl)-3',5'-di-O-acetyl-2'-deoxyuridine with aryl iodides in the presence of n-Bu(4)NF and triethylamine under a balloon of carbon monoxide produces 5-(2-acylethynyl)-3',5'-di-O-acetyl-2'-deoxyuridines in good yields at room temperature. The methodology has been extended to the preparation of alpha,beta-ynones from 1-alkynes and aryl iodides
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