Highly regioselective synthesis of N-acyl-2,3-dihydropyrrole or N-sulfonyl-2,3-dihydropyrrole derivatives by nano-palladium catalyzed cycloisomerization of 1,6-dienes
摘要:
Porous palladium nanoparticles were prepared using a solution-phase approach. Their structures and shapes were analyzed by XRD, EDS, TEM and HRTEM. These palladium nanoparticles were used to catalyze the cycloisomerization reaction of N,N-diallylamide or N,N-diallylsulfonamide, and N-acyl-23-dihydropyrrole or N-sulfonyl-2,3-dihydropyrrole derivatives were therefore synthesized with very high regioselectivity, and in good yields. The nano-palladium catalyst showed high efficiency and it can be reused several times. A hydropalladation mechanism was proposed for this reaction. (C) 2009 Published by Elsevier B.V.
N-acylpyrroles were synthesized via olefin ring-closingmetathesis of diallylamines and in situ oxidative aromatization in the presence of the ruthenium Grubbs catalyst and a suitable copper catalyst. In the presence of Cu(OTf)2 and CuBr2, the reaction afforded N-sulfonyl- and N-acylpyrroles, respectively, in one pot. Under an oxygen atmosphere, the reaction went smoothly without the need of hydroperoxide
Synthesis and electrochemical study of iron, chromium and tungsten aminocarbenes: Role of ligand structure and central metal nature
作者:Irena Hoskovcová、Jana Roháčová、Dalimil Dvořák、Tomáš Tobrman、Stanislav Záliš、Radka Zvěřinová、Jiří Ludvík
DOI:10.1016/j.electacta.2010.02.057
日期:2010.11
(b) the substitution on the carbene ligand and (c) the nature of the central metal atom. The analysis of measured data confirms that the reduction center is localized on the carbene moiety and is strongly influenced by both electronic and sterical properties of its substituents. The oxidation proceeds on the metal and depends mainly on its nature and on the π-acidity of the ligands. Electrochemistry
Study of the Origin of the Hindered Rotation of an Aryl Ring in Chromium Aminocarbene Complexes Bearing an Aromatic Ring Attached to the Carbene Carbon Atom
substituted chromiumaminocarbenecomplexes cis-tetracarbonyl[(η2-N-allyl-N-allylamino)(4-X-phenyl)carbene]chromium(0) (X = MeO, Me, H, Cl, CO2Me, CF3) were prepared by the reaction of the corresponding N,N-diallylamides with Na2Cr(CO)5 and Me3SiCl. Using dynamic NMR, the rotational barrier of the aryl ring in these complexes was established. The obtained values are higher for the complexes bearing electron