نتایج جستجو برای: alkynes
تعداد نتایج: 3647 فیلتر نتایج به سال:
Hydrosilylation reaction of various fluoroalkylated alkynes with Et(3)SiH in the presence of a catalytic amount of Co(2)(CO)(8) was investigated. The hydrosilylation of the alkynes having fluoroalkyl and aryl groups took place smoothly with good regioselectivity (ca. 80:20). In sharp contrast, the reaction of the alkynes having a fluoroalkyl group and a benzyl-type substituent, or various propa...
Carbon-carbon triple bonds of alkynes are ubiquitous. They serve as valuable starting materials that can be transformed into a vast array of diverse materials, with applications ranging from medicinal chemistry to electronic materials. The methods used to prepare alkynes involve stoichiometric reactions and the most popular install only a single carbon rather than uniting larger fragments. Thes...
Two amphiphilic palladium NNC-pincer complexes bearing hydrophilic tri(ethylene glycol) chains and hydrophobic dodecyl chains were designed and prepared for the development of a new aquacatalytic system. In water, these amphiphilic complexes self-assembled to form vesicles, the structures which were established by means of a range of physical techniques. When the catalytic activities of the ves...
Carbomagnesiation and carbozincation reactions are efficient and direct routes to prepare complex and stereodefined organomagnesium and organozinc reagents. However, carbon-carbon unsaturated bonds are generally unreactive toward organomagnesium and organozinc reagents. Thus, transition metals were employed to accomplish the carbometalation involving wide varieties of substrates and reagents. R...
Ene-yne cross-metathesis from alkynes and ethylene is a useful method to produce substituted conjugated butadiene derivatives. If this method has been used with aliphatic alkynes, it has however never been used starting from diarylacetylenes as internal alkynes. We show that the ene-yne cross-metathesis catalyzed by the second generation Hoveyda ruthenium catalyst provides the 2,3-diarylbuta-1,...
The addition of 4-trifluoromethyl-1-ethynylbenzene, phenylacetylene, or 4-ethynylanisole to P-mesityldiphenylmethylenephosphine, 1, produced photoluminescent 1,2-dihydrophosphinines 4a-c, respectively, in quantitative yield via a [4 + 2] cycloaddition. Limited reactivity was observed between 1 and non-aromatic alkynes. P-[Bis(trimethylsilyl)amino][(trimethylsilyl)methylene]phosphine, 2, and P-m...
Alkynes are used as building blocks in synthetic and medicinal chemistry, chemical biology, and materials science. Therefore, efficient methods for their synthesis are the subject of intensive research. Herein, we report the direct synthesis of alkynes from readily available carboxylic acids at room temperature under visible-light irradiation. The combination of an iridium photocatalyst with et...
The stereoselective germylzincation of internal alkynes delivering trisubstituted vinylgermanes is achieved via a radical chain process involving Ph3GeH and Et2Zn with AIBN as initiator. Excellent levels regiocontrol are observed for non-symmetric (aryl, alkyl)-substituted alkynes, well propargylic alcohols aryl-, alkyl-, or silyl-substituted alkynes. reaction can be combined in one pot the Cu(...
A method for the synthesis of 1,1-diborylalkenes through a Brønsted base catalyzed reaction between terminal alkynes and bis(pinacolato)diboron has been developed. The procedure allows direct synthesis of functionalized 1,1-diborylalkenes from various terminal alkynes including propiolates, propiolamides, and 2-ethynylazoles.
A novel iron-catalyzed transfer hydrogenation of alkynes to the corresponding alkenes applying formic acid as a hydrogen donor is reported. An in situ combination of Fe(BF(4))(2)·6H(2)O and tetraphos allows for highly selective hydrogenation of a broad range of aromatic and aliphatic alkynes tolerating different functional groups.
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