An intriguing, facile, and efficient oxidation and cyclization of alkynes catalyzed by Pd(OAc)2 in a fluorous biphasic system of N,N-dimethylacetamide (DMA) and perfluorodecalin directly with molecular oxygen is described, which opens an efficient access to tetrasubstituted furans. Under the optimized conditions, intermolecular reaction between diverse alkynes provides the corresponding mixture of regioisomers with appreciable selectivity. Intramolecular oxidation and cyclization of alkynes are also successfully demonstrated. The reaction proceeds efficiently under mild conditions with atmospheric oxygen as the sole oxidant.
Synthesis of Tetrasubstituted Furans via Sequential Pd(OAc)2/Zn(OTf)2-Catalyzed Oxidation and Cyclization of Aromatic Alkynes with Molecular Oxygen
作者:Huanfeng Jiang、Azhong Wang、Qiuxiang Xu
DOI:10.1055/s-0028-1088216
日期:2009.4
The development of a new method for the synthesis of tetrasubstituted furans using aromatic alkynes is reported. The strategy involves a tandem process of palladium-catalyzed oxidation and Zn(OTf)2-catalyzed cyclization in the presence of molecular oxygen.
Unexpected Base-Promoted Synthesis of Tetrasubstituted Furans via Palladium-Catalyzed Oxidation and Cyclization of Carbon-Carbon Triple Bond with Molecular Oxygen
A new approach to the synthesis of tetrasubstituted furans using aromatic alkynes catalyzed by PdCl2 in DMA (N,N-dimethylacetamide)-H2O with dioxygen as the sole oxidant is described, in which the oxygen atom of the furan was from water. The preliminary mechanistic understanding of this transformation was investigated.
Reaction control in heterogeneous catalysis using montmorillonite: switching between acid-catalysed and red-ox processes
作者:José Antonio Morales-Serna、Bernardo A. Frontana-Uribe、Rosario Olguín、Virginia Gómez-Vidales、Leticia Lomas-Romero、Erendira Garcia-Ríos、Ruben Gaviño、Jorge Cárdenas
DOI:10.1039/c6ra05293b
日期:——
The use of montmorillonite, modified with a super-acid (CF3SO3H) in the presence of hydroquinone as a radical scavenger and under a nitrogen atmosphere, induced the formation of tetrasubstituted furans as...