25699-85-8Relevant articles and documents
Enantioselective Direct Alkynylation of Ketones Catalyzed by Chiral CCN Pincer RhIIIComplexes
Ito, Jun-Ichi,Ubukata, Shino,Muraoka, Shun,Nishiyama, Hisao
, p. 16801 - 16804 (2016)
A direct asymmetric alkynylation of ketones with new chiral CCN Rh catalysts containing N-heterocyclic carbene and oxazoline hybrid ligands is described. The catalytic reaction of fluoroalkyl-substituted ketones, ArCOCF2X (X=F, Cl, H), with aromatic and aliphatic alkynes yielded the corresponding chiral propargyl alcohols with high enantioselectivity. Control and kinetic experiments suggested a bis(alkynyl) Rh intermediate as the active species for the C?C bond-forming step.
Steric effects on acetate-assisted cyclometallation ofmeta-substitutedN-phenyl andN-benzyl imidazolium salts at [MCl2Cp*]2(M = Ir, Rh)
Davies, David L.,Singh, Kuldip,Tamosiunaite, Neringa
, p. 13505 - 13515 (2021/10/12)
meta-SubstitutedN-phenyl,N′-methyl andN-benzyl,N′-methyl imidazolium salts undergo acetate-assisted cyclometallation to provide mixtures oforthoandparasubstituted cyclometallated complexes. The effect of the substituents on the isomer ratios is discussed; steric effects are more important in the 6-membered rings derived from theN-benzyl imidazolium salts than 5-membered rings from theN-phenyl salts. Comparisons are made to steric effects with some other common directing groups.
Framework-Copper-Catalyzed C?N Cross-Coupling of Arylboronic Acids with Imidazole: Convenient and Ligand-Free Synthesis of N-Arylimidazoles
Devarajan, Nainamalai,Suresh, Palaniswamy
, p. 2953 - 2960 (2016/09/28)
A convenient and environmentally benign synthesis of N-arylimidazoles has been demonstrated by a straightforward reaction catalyzed by the unsaturated coordination sites of Cu in the copper terephthalate metal–organic framework (Cu(tpa)-MOF). A series of N-arylimidazoles has been synthesized in excellent yields by the C?N cross-coupling reaction of arylboronic acids and imidazoles catalyzed by the Cu(tpa)-MOF using ethanol as a benign solvent. The present ligand-free catalytic system proceeds smoothly under mild conditions, avoids stoichiometric Cu reagents, tolerates many functional groups, has a wide substrate scope, and is feasible with other nitrogen heterocycles. The stability and heterogeneity of the catalyst is evidenced by the results of a heterogeneity test, and the catalyst can be reused several times without a loss of activity. The easy preparation of the catalyst, its stability, recovery by simple filtration, and reusability reveal Cu(tpa) MOF as a versatile catalyst for academic and industrial applications.
