Modulating Reactivity and Diverting Selectivity in Palladium-Catalyzed Heteroaromatic Direct Arylation Through the Use of a Chloride Activating/Blocking Group
作者:Benoît Liégault、Ivan Petrov、Serge I. Gorelsky、Keith Fagnou
DOI:10.1021/jo902515z
日期:2010.2.19
Through the introduction of an aryl chloride substituent, the selectivity of palladium-catalyzeddirectarylation may be diverted to provide alternative regioisomeric products in high yields. In cases where low reactivity is typically observed, the presence of the carbon−chlorine bond can serve to enhance reactivity and provide superior outcomes. From a strategic perspective, the C−Cl bond is easily
homogeneous palladium catalysts. Better yields were obtained with electron-deficient benzenesulfonylchlorides than with the electron-rich ones. Notably, useful substituents such as bromo or iodo on the benzenesulfonylchloride were tolerated, as no cleavage of the C-Br or C-I bonds was observed under these conditions. The use of Pd/C presents several advantages compared to the previously employed homogeneous
Eco-Friendly Solvents for Palladium-Catalyzed Desulfitative CH Bond Arylation of Heteroarenes
作者:Anoir Hfaiedh、Kedong Yuan、Hamed Ben Ammar、Bechir Ben Hassine、Jean-François Soulé、Henri Doucet
DOI:10.1002/cssc.201403429
日期:2015.5.22
Herein, we report the Pd‐catalyzed regioselective direct arylation of heteroarenes in which benzenesulfonyl chlorides are used as coupling partners through a desulfitative cross‐coupling that can be performed in diethyl carbonate (DEC) or cyclopentyl methyl ether (CPME) as green and renewable solvents or even in neat conditions instead of dioxane or dimethylacetamide (DMA). Under these solvent conditions
proton spectroscopy detected intermediates and uncovered the course of reactions in acetate-buffered [D4]methanol of primary cyclopropanediamines cis- and trans-2a with benzaldehyde (3a) or 2,2-dimethylpropanal (3b), of secondary cyclopropanediamines cis- and trans-2b with 3b, and of the ring-methylated cyclopropanediamine trans-14a and the aromatic aldehydes 3a and c. This study provided the basis
AbstractThe reactivity of pyrrole derivatives for palladium‐catalysed desulfitative arylation has been investigated. 1‐Methyl‐, 1‐phenyl‐ and 1‐benzylpyrroles were successfully coupled with a variety of benzenesulfonyl chlorides using a phosphine‐free catalyst. Highly regioselective arylations at carbon C2 of pyrroles were observed in all cases. A wide variety of substituents on the benzenesulfonyl derivative was tolerated.It should be noted that even bromo‐ and iodo‐benzenesulfonyl chlorides were successfully coupled with pyrrole derivatives without cleavage of the CBr or CI bonds, allowing further transformations. Surprisingly, with indoles, mixtures of C2‐ and C3‐arylation products were obtained.magnified image