Reagent

About: Reagent is a research topic. Over the lifetime, 60091 publications have been published within this topic receiving 1234928 citations. The topic is also known as: reagens.

β-Arylation of carboxamides via iron-catalyzed C(sp3)-H bond activation.

Abstract: Directed C(sp3)–H bond functionalization has been studied mainly by using precious metal catalysts, such as Pd, Ru, Rh, and Ir under harsh conditions. Generally, these metal-catalyzed C–H functionalization reactions are based on the formation of a C(sp3)-metallacycle. Iron-catalyzed C(sp3)–H functionalization has been studied mainly using radical processes. Functionalization of an unactivated C(sp3)–H bond via formation of a ferracycle intermediate is limited to stoichiometric reactions. We report here an iron/biphosphine-catalyzed directed arylation of a C(sp3)–H bond in an aliphatic carboxamide with an organozinc reagent in high yield under mild oxidative conditions. The choice of the directing group and of the biphosphine ligand was crucial for the success of this reaction. This reaction shows selectivity for a primary C–H over a secondary one and is sensitive to steric factors on both the amide and the Grignard reagent. Various β-arylated aliphatic carboxamides can be readily prepared by using this method.

A low-temperature solution phase route for the synthesis of silicon nanoclusters

Abstract: We report here a new solution phase synthesis for producing crystalline silicon nanoclusters at significantly lower temperatures than previously required. In addition, it is performed at ambient pressure and yields a particle surface that can be modified by chemical methods. This method has the potential to yield large amounts of silicon nanocrystals in addition to providing reliable control over size distribution and surface termination. In this synthesis we use the Zintl salt KSi as a starting reagent. KSi is synthesized by reacting excess K with silicon at 650{degree}C for three days and subliming off the excess K at 275{degree}C under vacuum. The purity of the air-sensitive, black solid is verified by powder X-ray diffraction. 23 refs., 1 fig.

Ni- or Cu-Catalyzed Cross-Coupling Reaction of Alkyl Fluorides with Grignard Reagents

Abstract: n-Octyl fluoride underwent a cross-coupling reaction with n-propylmagnesium bromide in the presence of 1,3-butadiene using NiCl2 as a catalyst at room temperature to give undecane in moderate yields. This alkyl−alkyl cross-coupling proceeded more efficiently when CuCl2 was employed instead of NiCl2. Addition of 1,3-butadiene dramatically improved the yields of the coupling products from primary alkyl Grignard reagents in both Ni- and Cu-catalyzed reactions. Alkyl fluorides efficiently reacted with tertiary alkyl and phenyl Grignard reagents using CuCl2 in the absence of 1,3-butadiene to afford the coupling products in high yields. The competitive reaction of a mixture of alkyl halides (R−X; X = F, Cl, Br) with nC5H11MgBr showed that the reactivities of the halides increase in the order R−Cl < R−F < R−Br. In contrast, in the Cu-catalyzed reaction with PhMgBr, the reactivities increase in the order R−Cl < R−Br < R−F.