Palladium-Catalyzed anti-Markovnikov Oxidative Acetalization of Activated Olefins with Iron(III) Sulphate as Benign Reoxidant

This paper discloses the efficient palladium-catalyzed anti-Markovnikov oxidative acetalization of activated terminal olefins with iron(III) sulfate as benign reoxidant. This methodology depicts mild reaction conditions, high regioselectivity toward anti-Makovnikov products...

Tuning the Liquid Crystallinity of Cholesteryl-o-Carborane Dyads: Synthesis, Structure, Photoluminescence, and Mesomorphic Properties

A set of mesomorphic materials in which the o-carborane cluster is covalently bonded to a cholesteryl benzoate moiety (mesogen group) through a suitably designed linker is described. The olefin cross-metathesis between appropriately functionalized styrenyl-o-carborane derivatives and a terminal alkenyl cholesteryl benzoate mesogen (all type I terminal olefins) leads to the desired trans-regioisomer, which is the best-suited configuration to obtain mesomorphic properties in the final materials. The introduction of different substituents (R = H (M2), Me (M3), or Ph (M4)) to one of the carbon atoms of the o-carborane cluster (Ccluster) enables the tailoring of liquid crystalline properties. Compounds M2 and M3 show the chiral nematic (N*) phase, whereas M4 do not show liquid crystal behavior. Weaker intermolecular interactions in the solid M3 with respect to those in M2 may allow the liquid crystallinity in M3 to be expressed as enantiotropic behavior, whereas breaking the stronger intermolecular interaction in the solid state of M2 leads directly to the isotropic state, resulting in monotropic behavior. Remarkably, M3 also displays the blue phase, which was observed neither in the chiral nematic precursor nor in the styrenyl-cholesterol model (M5) without an o-carborane cluster, which suggests that the presence of the cluster plays a role in stabilizing this highly twisted chiral phase. In the carborane-containing mesogens (M2 and M3), the o-carborane cluster can be incorporated without destroying the helical organization of the mesophase.

Direct oxidative carboxylation of terminal olefins to cyclic carbonates by tungstate assisted-tandem catalysis

Tungstate catalysts are well established for olefin epoxidation reactions, while their catalytic activity for CO2 insertion in epoxides is a more recent discovery. This dual reactivity of tungstate prompted the...

Computational insights into Ir(iii)-catalyzed allylic C–H amination of terminal alkenes: mechanism, regioselectivity, and catalytic activity

DFT studies on Ir(iii)-catalyzed branch-selective allylic C–H amination of terminal olefins with methyl dioxazolone have been carried out to investigate the mechanism, including the origins of regioselectivity and catalytic activity difference.

Carbonylation of olefins by carbon monoxide and alcohols in the presence of Pd-complex catalytic system

In order to develop new, efficient and environmentally friendly methods for the preparation of practically valuable esters of carboxylic acids, studies of the hydroalkoxycarbonylation reaction of a number of terminal olefins of normal structure (hexene-1, heptene-1, octene-1, nonene-1) with carbon monoxide and alcohols in presence of metal complex catalysts based on palladium phosphine complexes at low carbon monoxide pressures (≤ 20 atm).Two-and three-component systems based on PdCl2 and Pd(Acac)2, PdCl2(PPh3)2, Pd(PPh3)4 complexes containing a free ligand (PPh3) as a stabilizer and Bronsted acid (TsOH) as a promoter were studied as catalysts. It was shown that only the three-component systems PdCl2-PPh3-TsOH, PdCl2(PPh3)2-PPh3-TsOH, Pd(Acac)2-PPh3-TsOH, and Pd(PPh3)2-PPh3-TsOH have the highest catalytic activity in the studied reactions. It was found that the reaction of hydroalkoxycarbonylation of α-olefins proceeds with the formation of a mixture of linear and branched products. The influence of various conditions of the reaction (the ratio of the initial reagents and the components of the catalytic systems, temperature, CO pressure, duration) on the course of the process and on the yield of the target products was investigated. The optimal parameters of the studied reactions have been found.