Dichloro-Bis(aminophosphine) Complexes of Palladium: Highly Convenient, Reliable and Extremely Active Suzuki-Miyaura Catalysts with Excellent Functional Group Tolerance
作者:Jeanne L. Bolliger、Christian M. Frech
DOI:10.1002/chem.200903309
日期:2010.4.6
systems, is a highlyconvenient, reliable, and extremelyactive Suzuki catalyst with excellentfunctionalgrouptolerance that enables the quantitative coupling of a wide variety of activated, nonactivated, and deactivated and/or sterically hindered functionalized and heterocyclic aryl and benzyl bromides with only a slight excess (1.1–1.2 equiv) of arylboronic acid at 80 °C in the presence of 0.2 mol % of
Room-Temperature Photoinduced Direct C–H-Arylation via Base-Promoted Homolytic Aromatic Substitution
作者:María E. Budén、Javier F. Guastavino、Roberto A. Rossi
DOI:10.1021/ol3034687
日期:2013.3.15
biaryl syntheses by photoinduced direct C–H arylation of benzene and thiophene in the presence of t-BuOK is reported. The reaction proceeds through photo- and base-promoted homolyticaromaticsubstitution. The o-, m- and p- substituted ArI, as well as the electron-donating and electron-withdrawing nature of the substituents were found be good to excellent substrates. Heteroaryl, ArBr, ArCl and double C–H
Benzo-fused tri- to heptacyclic heteroarenes were effectively constructed by the rhodium-catalyzed dehydrogenative coupling of phenylheteroarenes with alkynes. Using alkenes as coupling partners, dehydrogenative alkenylation took place selectively on the phenyl moiety of phenylheteroarenes. Several experiments with deuterium-labeled substrates indicated that double C-H bond cleavages take place even in the reaction with alkenes.
Redox‐Divergent Construction of (Dihydro)thiophenes with DMSO
We report herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr, respectively. This strategy can serve for the programmable and concise synthesis of bioactive and functional molecules.
3-Arylthiophenes were prepared from 2,5-dichlorothiophene in two steps. 2,5-Dichlorothiophene reacted regioselectively with various aromatic compounds in the presence of AlCl3 under mild conditions to give 4-aryl-2-chlorothiophenes. The latter compounds were easily converted to the corresponding 3-arylthiophenes by catalytic dechlorination in good yields.