Copper-catalyzed oxidative esterification of ortho-formyl phenols without affecting labile formyl group
作者:Yong Zheng、Wei-Bin Song、Li-Jiang Xuan
DOI:10.1016/j.tetlet.2015.06.024
日期:2015.7
A copper-catalyzed oxidativeesterification of ortho-formyl phenols with aldehydesusing TBHP as oxidant in water is developed. Besides aromatic and aliphatic aldehydes, benzylic alcohols are also suitable for this reaction. The sensitive formyl group remains intact under oxidative conditions. This method provides an alternative protocol for classical esterification reactions.
A new directing group assisted method for the synthesis of aryl esters is described. In this Cu(II)-mediated reaction, 2-formylphenols and 2-acetylphenols are easily converted to the aryl esters by treatment with a new aroylating agent 2-bromoacetophenone. In addition, a new external bromine free method for the synthesis of important synthons 2,2-dibromoacetophenones from 2-bromoacetophenones is described
copper-catalyzed chemoselective oxidative O-aroylation of 2-acetylphenols, alkyl salicylates and 1,3-dicarbonyl compounds with a wide range of styrene derivatives are described. This approach provides an efficient chemoselective preparation of phenol, alkyl salicylate and enol esters in good to excellent yields. This method represents an alternative protocol for the classical esterification reactions.