نتایج جستجو برای: heck cross coupling
تعداد نتایج: 633215 فیلتر نتایج به سال:
Coupling reactions, most prominently Heck and Suzuki couplings but also Sonogashira coupling and allylic substitution, are established catalytic transformations for the synthesis of fine chemicals. The recovery of catalytically active complexes from such coupling reactions, by the concept of covalent binding to soluble polymers, has been studied by various research groups. This research, addres...
Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (nonoxidative) Heck reaction between a vinyl b...
The C-C coupling of N,N'-bis(5-norbornene-2,3-dicarboximide) (3) and N,N'-bis(7-oxa-5-norbornene-2,3-dicarboximide) (6) with aryl and heteroaryl iodides gave under reductive Heck conditions the C-aryl(hetaryl), substituted N,N'-bistricyclic imides 7a-f and 8a,b. The fused spiro-1,3-indandionolylpyrrolidine compounds, 9, 10 and 11 were also obtained from ninhydrine, sarcosine and 3 or 6 via [3+2...
Branched-selective oxidative Heck coupling reactions have been developed between arylboronic acids and electronically unbiased terminal alkenes. The reactions exhibit high catalyst-controlled regioselectivity favoring the less common branched isomer. The reactions employ a catalyst composed of Pd(TFA)2/dmphen (TFA = trifluoroacetate, dmphen = 2,9-dimethyl-1,10-phenanthroline) and proceed effici...
6-Amino-3-(2'-deoxy-beta-D-ribofuranosyl)-5-nitro-1H-pyridin-2-one (4), a C-glycoside exhibiting the nonstandard pyDDA hydrogen-bonding pattern, was synthesized via Heck coupling. The nitro group greatly enhances the stability of the nucleoside toward acid-catalyzed epimerization without leading to significant deprotonation of the heterocycle at physiological pH. These results make nucleoside 4...
A(2)B(2)-type push-pull porphyrins with a strong intramolecular dipole moment have been prepared via Heck and Suzuki coupling reactions as novel materials for use in nonlinear optics (NLO); they display saturable (SA) and reverse saturable absorption (RSA) properties at 532 nm and their nonlinear optical response is characterized by RSA occurring at lower intensity levels whereas the onset of S...
The Heck coupling of aryl iodides with pyranoid glycals using a catalytic amount of Pd(OAc)(2) to form pyranoid aryl C-glycosides has been achieved. The reaction takes place smoothly in the presence of Ag(2)CO(3) and Cu(OAc)(2) (or DMSO) in acetonitrile. This arylation process, which occurs in a highly regio- and stereo-selective manner, provides a simple, mild, and efficient approach to the sy...
Axially chiral mono(NHC)-Pd(II) and mono(NHC)-Au(I) complexes with one side shaped 1,1'-biphenyl backbone have been prepared from chiral 6,6'-dimethoxybiphenyl-2,2'-diamine. The complexes were characterized by X-ray crystal structure diffraction. The Pd(II) complex showed good catalytic activities in the Suzuki-Miyaura and Heck-Mizoroki coupling reactions, and the (S)-Au(I) complexes also showe...
Carbon–carbon bond formation by sp–sp or sp–sp crosscoupling is a key transformation in organic synthesis. Many methods, typically involving transition metal catalysis, are known, and the recent recognition of Richard F. Heck, Ei-ichi Negishi and Akira Suzuki by the Royal Swedish Academy of Sciences (Stockholm, Sweden) when they were awarded the Nobel Prize in Chemistry (2010) underlines the im...
N,N-Diaryl aminostilbenes and N,N-diaryl aminostyrenes are versatile compounds that have found exciting applications in the field of photochemistry; most of these compounds are patented and they are widely used as electro-photographic photoconductors and photoreceptors. Recent reports have demonstrated, for example, that these compounds can exhibit an amino-conjugation effect in their fluoresce...
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