نتایج جستجو برای: phosphines
تعداد نتایج: 579 فیلتر نتایج به سال:
Abstract (4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and 3-atom to form both 7-membered carbocycles as well heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis Brønsted acids some rare of boronic acid catalysis photocatalysis. analogy our pr...
A regioselective [3 + 2] cycloaddition of benzofuranone type active olefins with allenoates catalyzed by trivalent phosphines has been developed, which provided an easy access to enriched functionalized spirocyclic benzofuranones. The reactions accommodated a number of benzofuranone type electron-deficient olefins and allenoates to give the desired 3-spirocyclopentane benzofuran-2-ones or 2-spi...
Ynones are efficiently reduced with a mild hydride donor in the presence of a catalytic amount of nucleophilic phosphines. The reactions are selective 1,2-reductions that give propargyl alcohols in yields of up to 96%. It is proposed that success in these reactions depends on the activation of ynones by a Lewis base catalyst. A protic additive plays a key role in suppressing the undesired react...
An overview is given of the chemistry of tris(azolyl)phosphines with focus on their preparation and application in coordinationand organometallic chemistry and catalysis. These systems share with the more abundant tris(pyrazolyl)borates and -methanes the ability to function as tridentate nitrogen ligands with hemilabile character, but the additional phosphine donor site grants them bifunctional...
Reactions of (η-RC5H4)Fe(CO)2I (R = H, Me) complexes with phosphine ligands PR′3 (R′ = Ph, m-Tol, p-C6H4OMe, p-C6H4Cl, p-C6H4F) have been performed under solvent-free conditions in the melt phase and generally yielded the ionic products [(η5-RC5H4)Fe(CO)2PR′3]I rather than the CO substituted products (η5-RC5H4)Fe(CO)(PR′3)I. The complexes have been characterised by IR, NMR and MS techniques. By...
[equation--see text] The N-arylation of indoles, including a variety of substituted ones, has been carried out using bulky, electron-rich phosphines as the supporting ligand in combination with Pd(2)(dba)(3). Using this catalyst system, the efficient coupling of indole and a variety of substituted indoles with aryl iodides, bromides, chlorides, and triflates can be achieved.
Palladium dimers with sterically hindered phosphines have been shown to be excellent pre-catalysts for the aminocarbonylation of aryl halides to yield amides and one of them has been successfully employed as a pre-catalyst for the synthesis of (11)C-radiolabelled amides for PET imaging.
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