Wednesday, July 25, 2012

Microwave-assisted palladium mediated decarbonylation reaction: synthesis of eulatachromene


Microwave-assisted decarbonylation reactions were investigated using a palladium catalyst. A large number of aldehydes can be decarbonylated efficiently with lower catalyst loadings and under shorter reaction times compared to conventional heating. A successful decarbonylation led to the synthesis of natural product eulatachromene in three steps starting from easily available materials.


Graphical abstract: Microwave-assisted palladium mediated decarbonylation reaction: synthesis of eulatachromene


Highly regioselective synthesis of aryl chalcogenides through C–H functionalization of arenes

We report here the regioselective synthesis of aryl chalcogenides through the iridium-catalyzedmeta C–H borylation followed by copper-catalyzed C–S coupling reaction with chalcogenide sources in one pot, giving the 3,5-disubstituted aryl chalcogenides with high regioselectivity and good yields.

Graphical abstract: Highly regioselective synthesis of aryl chalcogenides through C–H functionalization of arenes


An efficient copper-catalyzed formation of highly substituted pyrazoles using molecular oxygen as the oxidant

An efficient Cu-catalyzed formation of tetra-substituted pyrazoles is reported. In this atom economic process, readily available enamines and nitriles are reacted by C–C and N–N bond formation. Oxygen has been successfully used as the oxidant, which has important economic and environmental advantages. A broad scope of enamines and nitriles can be utilized in this process.

Graphical abstract: An efficient copper-catalyzed formation of highly substituted pyrazoles using molecular oxygen as the oxidant




TBHP/I2-promoted oxidative coupling of acetophenones with amines at room temperature under metal-free and solvent-free conditions for the synthesis of α-ketoamides

A novel and efficient TBHP/I2-promoted oxidative coupling reaction of acetophenones with amines for the synthesis of α-ketoamides has been developed. The reactions proceeded smoothly at room temperature under metal-free and solvent-free conditions and generated the corresponding products in good yields.


Graphical abstract: TBHP/I2-promoted oxidative coupling of acetophenones with amines at room temperature under metal-free and solvent-free conditions for the synthesis of α-ketoamides

A simple and facile Heck-type arylation of alkenes with diaryliodonium salts using magnetically recoverable Pd-catalyst


The Heck-type arylation of alkenes was achieved in aqueous polyethylene glycol using a magnetically recoverable heterogenized palladium catalyst employing diaryliodonium salts under ambient conditions. The benign reaction medium and the stability of the catalyst are the salient features of this simple and facile protocol.


Graphical abstract: A simple and facile Heck-type arylation of alkenes with diaryliodonium salts using magnetically recoverable Pd-catalyst