20488-44-2

Upstream product

• 20488-45-3 cis-4-Benzoylstilbene 
• 134-84-9 4-Methylbenzophenone 
• 100-52-7 benzaldehyde 
• 134-85-0 4-chlorobenzophenone 
• 201852-49-5 potassium (E)-trifluoro(styryl)borate 
• 100-42-5 styrene 
• 90-90-4 (4-bromophenyl)(phenyl)methanone 
• 6783-05-7 trans-2-phenylvinylboronic acid 
• 140-10-3 (E)-3-phenylacrylic acid 
• 55274-11-8 [(4-benzoylphenyl)methyl]triphenylphosphonium bromide 

Relevant academic research and scientific papers

Triplet Pathways in the cis -->/<-- trans Photoisomerization of 4-Acetyl- and 4-Benzoyl-stilbene

The photochemical properties of 4-acetylstilbene (AS) and 4-benzoylstilbene (BS) have been studied in various solvents using steady-state irradiation and ns laser flash photolysis.The quantum yields of trans -->/t->c, Φc->t) are substantial (>/=0.3) over a wide temperature range, while the quantum yield of fluorescence is small even at -196 deg C (e.g. Φf3t*) and the cis (3c*) triplet state, respectively, since at -196 deg C intersystem crossing occurs without significant configurational changes.Apart from small spectral differences BS behaves similarly.Quenching measurements by ferrocene of Φt->c, in comparison with those of the triplet decay, support that the triplet state is intermediate in the trans --> cis photoisomerization pathway.The spectral and kinetic features of the triplet state are interpreted on the basis of the intermediacy of the twisting step from 3c* to the perpendicular conformation (3p*) in the cis --> trans photoisomerization pathway, the 3t* -->/3p* equilibrium and decay to the ground states via the 3p* --> 1p intersystem-crossing step.

An effective Pd nanocatalyst in aqueous media: Stilbene synthesis by Mizoroki-Heck coupling reaction under microwave irradiation

Aqueous Mizoroki-Heck coupling reactions under microwave irradiation (MW) were carried out with a colloidal Pd nanocatalyst stabilized with poly(N-vinylpyrrolidone) (PVP). Many stilbenes and novel heterostilbenes were achieved in good to excellent yields starting from aryl bromides and different olefins. The reaction was carried out in a short reaction time and with low catalyst loading, leading to high turnover frequency (TOFs of the order of 100 h-1). The advantages like operational simplicity, high robustness, efficiency and turnover frequency, the utilization of aqueous media and simple product work-up make this protocol a great option for stilbene syntheses by Mizoroki-Heck reaction.

Bulky monodentate biphenylarsine ligands: Synthesis and evaluation of their structure effects in the palladium-catalyzed Heck reaction

Biphenyl-based arsine ligands were prepared in two-step fashion by Pd-catalyzed arsination and microwave-assisted Suzuki-Miyaura coupling, providing sterically demanding arsine ligands in overall isolated yields up to 82 % as air-stable solids. Short reaction times were achieved with the assistance of microwave irradiation in the direct and simple described protocol for the synthesis of biarylarsine ligands. The activities of the biphenyl arsine ligands were explored in Pd-catalyzed Heck coupling. As a general trend, the ligands with "blocked" ortho-positions on the non-arsine-containing ring of the biphenyl backbone performed more efficiently in the coupling reaction. This catalytic system allowed several interesting stilbenes to be obtained in very good yields. Sterically demanding biphenyl-based arsine ligands were prepared in high overall yields by microwave-assisted Suzuki-Miyaura coupling. The ligands were evaluated in the Pd-catalyzed Heck coupling reaction; the most active were those with "blocked" ortho-positions on the non-arsine-containing ring of the biphenyl backbone.

Activation of CX (=Cl, Br) bond in aryl halides toward the palladium-catalyzed Heck reaction using 2,6-bis(diphenylphosphino)pyridine

The 2,6-bis(diphenylphosphino)pyridine/palladium catalytic system successfully catalyzes the Heck coupling reaction of less reactive aryl chlorides as well as aryl bromides with styrene to give the corresponding olefins in reasonable yields. TBAB (tetrabu

Mizoroki-Heck reactions catalyzed by palladium dichloro-bis(aminophosphine) complexes under mild reaction conditions. the importance of ligand composition on the catalytic activity

Dichloro-bis(aminophosphine) complexes of palladium with the general formula [(P{(NC5H10)3-n(C6H 11)n})2Pd(Cl)2] (where n = 0-2) are easily accessible, cheap and air stable, highly active and universally applicable C-C cross-coupling catalysts, which exhibit an excellent functional group tolerance. The ligand composition of amine-substituted phosphines (controlled by the number of P-N bonds) was found to effectively determine their catalytic activity in the Heck reaction, for which nanoparticles were demonstrated to be their catalytically active form. While dichloro{bis[1, 1′,1′′-(phosphinetriyl)tripiperidine]}palladium (1), the least stable complex (towards protons) within the series of [(P{(NC5H 10)3-n(C6H11)n}) 2Pd(Cl)2] (where n = 0-3), is a highly active Heck catalyst at 100 °C and, hence, a rare example of an effective and versatile Heck catalyst that efficiently operates under mild reaction conditions (100 °C or below), a significant successive drop in activity was noticed for dichloro-bis(1,1′-(cyclohexylphosphinediyl)dipiperidine)palladium (2, with n = 1), dichloro-bis(1-(dicyclohexylphosphinyl)piperidine)palladium (3, with n = 2) and dichloro-bis(tricyclohexylphosphine)palladium (4, with n = 3), of which the latter is essentially inactive (at least under the reaction conditions applied). This trend was explained by the successively increasing complex stability and its ensuing retarding effect on the (water-induced) generation of palladium nanoparticles thereof. This interpretation was experimentally confirmed (initial reductions of 1-4 into palladium(0) complexes of the type [Pd(P{(NC5H10)3-n(C6H 11)n})2] (where n = 0-3) were excluded to be the reason for the activity difference observed as well as molecular (Pd 0/PdII) mechanisms were excluded to be operative) and thus demonstrates that the catalytic activity of dichloro-bis(aminophosphine) complexes of palladium can-in reactions where nanoparticles are involved-effectively be controlled by the number of P-N bonds in the ligand system.

Aryldiazonium silica sulfates as efficient reagents for Heck-type arylation reactions under mild conditions

An efficient and straightforward procedure for Heck-type arylation reactions was studied using aryldiazonium silica sulfates and olefins in the presence of a catalytic amount of Pd(OAc)2. These reactions were carried out in water at room temperature without using a base or additional ligands. The use of a non-toxic solvent, a simple and clean work-up, short reaction times, and good yields are advantages of this method.

Mizoroki-Heck cross-couplings of 2-acetyl-5-bromobenzofuran and aryl halides under microwave irradiation

Mizoroki-Heck cross-coupling reactions of 2-acetyl-5-bromobenzofuran as well as activated and deactivated aryl bromides with various olefins were investigated under both thermal as well as microwave irradiating conditions in open air using water solvent.

General reaction conditions for the palladium-catalyzed vinylation of aryl chlorides with potassium alkenyltrifluoroborates

(Chemical Equation Presented) Activated and deactivated aryl and heteroaryl chlorides are efficiently cross-coupled with potassium vinyl- and alkenyltrifluoroborates using 4-hydroxyacetophenone oxime derived palladacycle as precatalyst in 1 to 3 mol % Pd loading, Binap as ligand, and Cs 2CO3 as base in DMF at 120°C. The reactions can also be performed using Pd(OAc)2 as Pd(0) source, although with lower efficiency. Bidentate ligands such as Binap and dppp can be used, the former being the best choice. Only in the case of deactivated aryl chlorides should the reaction temperature be increased to 160°C to achieve good yields. The corresponding cross-coupled compounds, such as styrenes, stilbenes, and alkenylarenes, are obtained in good yields and with high regio- and diastereoselectivity. 2009 American Chemical Society.

Nanocrystalline magnesium oxide stabilized palladium(0): An efficient heterogeneous catalyst for heck and sonogashira coupling of aryl halides

Nanocrystalline magnesium oxide supported palladium(0) catalyst [NAP-Mg-Pd(0)], prepared by the counter-ion stabilization of PdCl 42 followed by reduction with hydrazine hydrate, was effectively used in the Heck olefination of haloarenes (chloro, bromo, and iodo) to afford good to excellent yields of substituted olefins. This ligand-free heterogeneous NAP-Mg-Pd(0) catalyst was quantitatively recovered from the reaction by a simple filtration and reused for a number of cycles with almost no loss of activity. Moreover, NAP-Mg-Pd(0) efficiently catalyzed the Sonogashira coupling of haloarenes with terminal alkynes without any copper co-catalyst under milder conditions to afford excellent yields of substituted alkynes. Georg Thieme Verlag Stuttgart.

Exploiting noninnocent (E,E)-dibenzylideneacetone (dba) effects in palladium(0)-mediated cross-coupling reactions: Modulation of the electronic properties of dba affects catalyst activity and stability in ligand and ligand-free reaction systems

The reactivity of palladium(0) complexes, [Pd2 0(dba-n,n′-Z)3] (n,n′-Z = 4,4′-F; 4,4′-CF3; 4,4′-H; 4,4′-MeO) and [Pd 0(dba-n,n′-Z)2] (n,n′-Z = 4,4′-CF 3; 4,4′-H; 3,3′,5,5′-OMe),