Copper-Assisted Synthesis of 2-Hydroxyphenyl-1,2-diones from Phenols and 2-Oxoaldehydes
An efficient copper(II)-catalyzed protocol for the ortho-functionalization of phenols was developed. A wide variety of 2-oxoaldehydes and phenols were tolerated, and the corresponding 2-hydroxyphenyl-1,2-diones were afforded in appreciable yields.
One-pot synthesis of unsymmetrical benzils by oxidative coupling using selenium dioxide and p-toluenesulfonic acid monohydrate
The oxidative coupling of the α-carbon atom of aromatic ketones with unactivated arenes in the presence of selenium dioxide and p-toluenesulfonic acid monohydrate is described. A number of unsymmetrical benzils have been prepared in good yields (38-75 % with high regioselectivity. The generality and functional tolerance of this new protocol is demonstrated. The mechanistic pathway for the oxidative coupling reaction is also described. The reaction displays superiority in terms of minimization of steps with the C-C bond formation promoted by SeO2 and pTsOH·H2O. This method is advantageous as the reactants used as the solvent can be recovered. Copyright
One-pot synthesis of unsymmetrical benzils from aryl methyl ketones and arenes in the presence of selenous acid catalysed by p-toluenesulfonic acid monohydrate
A modified one-pot method for the synthesis of unsymmetrical and heteroaryl benzils from substituted acetophenones and unactivated or weakly activated arenes by the use of H2SeO3 and p-TsOH·H 2O as catalysts at 35°C is established. The present method is regioselective and avoids the use of p-TsOH·H2O in stoichiometric amount in the presence of H2SeO3 and afforded unsymmetrical benzils in good yields.