An efficient phosphine-free direct C–Harylation of thiophenes at the α-position has been developed at low catalyst loading of bis(alkoxo)palladium complex (Cat.I, 0.1–0.2 mol %). The developed synthetic method can be applied to the synthesis of α-aryl/heteroaryl thiophenes from aryl or heteroaryl bromides in good to excellent yields and is compatible with the substrates bearing electron-donating or
Ligand-less palladium-catalyzed direct 5-arylation of thiophenes at low catalyst loadings
作者:Julien Roger、Franc Požgan、Henri Doucet
DOI:10.1039/b819912d
日期:——
Ligand-less Pd(OAc)2 provides a very efficient catalyst for the direct5-arylation of thiophenederivatives. With this catalyst, a low palladium concentration (0.1–0.001 mol%) should be employed in order to obtain high yields of coupling products. At higher concentrations a fast formation of inactive “Pd black” generally occurs. Substrates/catalysts ratios up to 100000 can be employed with the most
Solvent-Free Palladium-Catalyzed Direct Arylation of Heteroaromatics with Aryl Bromides
作者:Souhila Bensaid、Henri Doucet
DOI:10.1002/cssc.201100771
日期:2012.8
course of catalyzed directarylations. Some palladium‐catalyzed directarylations of heteroaromatics can be advantageously performed without any solvent. In the presence of palladiumcatalysts (1 mol %) and potassium acetate as the base, the direct 5‐arylation of some thiazoles, thiophenes, furans, or pyrroles with arylbromides as coupling partners proceeds highly regioselectively and in moderate to
A dihydroindacene compound represented by the following formula (1):
wherein R
1
is identical or different from each other, and each denotes a hydrogen atom, alkyl which may be substituted, alkenyl which may be substituted, alkynyl which may be substituted, alkoxy which may be substituted, alkylthio which may be substituted, aryl which may be substituted, aryloxy which may be substituted, or the like; R
2
to R
5
are identical or different from each other, and each denote a hydrogen atom, alkyl which may be substituted, alkenyl which may be substituted, or the like;
p is 0, 1, or 2; and
ring structures A and B are identical or different from each other, and each denote a benzene ring which may be substituted, a thiophene ring which may be substituted, or the like.
of an air‐stable, robust palladium/tridentate phosphane catalyst in direct CH and CCl activation reactions is reported (see scheme; DMAc=N,N‐dimethylacetamide, TBAB=tetra‐n‐butylammonium bromide). Electron‐rich, electron‐poor, and polysubstituted furans (X=O), thiophenes (X=S), pyrroles (X=NR5), and thiazoles were arylated with chloroarenes in the presence of the catalyst.
穿上它的环:在直接C中的使用对空气稳定的,坚固的钯/三齿磷烷催化剂 H和13 C 氯活化反应报道(参见方案;的DMAc = Ñ,Ñ二甲基乙酰胺,TBAB =四Ñ -丁基溴化铵)。在催化剂存在下,富电子,贫电子和多取代的呋喃(X = O),噻吩(X = S),吡咯(X = NR 5)和噻唑被氯芳烃芳基化。