This work emphasizes the synthesis of substituted vinyl arenes by reductive coupling of aryl halides with vinyl bromides under mild and easy-to-operate nickel-catalyzed reaction conditions. A broad range of aryl halides, including heteroaromatics, and vinyl bromides were employed to yielding products in moderate to excellent yields with high functional-group tolerance. The nickel-catalytic system displays good chemoselectivity between the two C(sp )-halide coupling partners, thus demonstrating a mechanistic pathway distinct from other stepwise protocols.

We use a chemically accurate (4 kJ/mol) hybrid MP2:(PBE+D2) + ΔCCSD(T) method to determine relative stabilities of all possible π-complexes, alkoxides, and carbenium ions formed from propene, butene, and pentene with the Al(2)O(7) Brønsted acid site in H-FER. The energetic order is carbenium ions > tert-alkoxides > π-complexes as well as primary and secondary alkoxide species. Primary carbenium ions are not stationary points on the potential energy surface. The energetically most stable C3, C4, and C5 surface species are 2propoxide, 2-butoxide, and the 2-methyl-2-butene π-complex with energies of −78, −81, and −85 kJ/mol, respectively, for formation from the corresponding alkenes. Compared to the present results, the widely applied PBE+D2 approach overbinds all species, and the energy differences are 18−24, 25−45, and 48−71 kJ/mol for π-complexes, alkoxides, and carbenium ions. Enthalpies and Gibbs free energies are calculated for 323 and 623 K within the harmonic approximation. The calculated adsorption enthalpy of trans-2-pentene, −93 kJ/mol, is in agreement with the experimental value, −92 kJ/mol [Schallmoser et al. J. Am. Chem. Soc. 2017, 139, 8646]. Entropy favors the more mobile species (carbenium ions, π-complexes), and the Gibbs free energy order becomes carbenium ions and tert-alkoxides > primary and secondary alkoxides > π-complexes.

The present work highlights unprecedented Ni-catalyzed reductive coupling of unactivated alkyl iodides with aryl acid chlorides to efficiently generate alkyl aryl ketones under mild conditions.

Epithelial-mesenchymal transition (EMT) is implicated in the metastasis of human prostate cancer (PCa). Notch signaling has been established as a regulator of EMT. Notch-4 has emerged as a mammary proto-oncogene and a target in several cancers. However, the role and the mechanism of action of Notch-4 in PCa are still unclear. In the present study, we first observed a marked increase in Notch-4 expression in the PCa cell lines DU145, PC3 and LnCAP compared with the non-malignant prostate epithelial cell line RWPE1. Knocking down the expression of Notch-4 suppressed the viability and proliferation in the PCa cell lines DU145 and PC3. Also, further study showed that a decline in Notch-4 significantly promoted apoptosis in PC3 cells. Notch-4 silencing also resulted in decreased cell migration and invasion and affected the expression of EMT markers. We hypothesized that Notch-4 ablation suppresses the activity of NF-κB, so we used PMA to stimulate NF-κB p50 and p65 activation in PC3 cells. The results indicate that PMA treatment impaired the action of Notch-4 ablation in the biology of PC3 cells including cell growth, apoptosis, migration, invasion and EMT. The results of the present study show that RNAi targeting against Notch-4 expression suppresses PCa progression.

The rates and mechanism of the reactions of a series of aryl-ligated, anionic palladium(o) complexes Ar-Pdo-(PPh,); with para-substituted iodobenzenes were investigated by means of transient electrochemistry. The reaction was found to be first order in each reactant and to proceed similarly to oxidative addition of aryl halides to the halide-ligated species X-Pdo(PPh,);, although much faster and less sensitive to electronic factors. Owing to the short lifetime (fl,2z 1-5 ms) of the product of this reaction, it could not be characterized in detail. However, based on kinetic results, this transient species is thought to be an anionic pentacoordinated bisarylpalladium (11) complex, which undergoes rapid loss of halide ligand to yield, most probably, a bisarylpalladium(rr) neutral species. Based on the study of this reaction and on previously reported results, we propose a mechanism for the palladium-catalyzed homocoupling of aryl halides consisting of a catalytic cycle initiated by oxidative addition of an aryl halide to a zerovalent tris-ligated palladium center. Two-elec-