Direct Synthesis of Cyclic Ketals of Acetophenones by Palladium-Catalyzed Arylation of Hydroxyalkyl Vinyl Ethers
作者:Mats Larhed、Anders Hallberg
DOI:10.1021/jo971454q
日期:1997.10.1
Reaction of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, or di(ethylene glycol) vinyl ether with aryl triflates, aryl bromides, or iodobenzene in presence of a catalytical amount of palladium acetate and the bidentate ligand DPPP provides a direct entry to cyclic ketals of acetophenones. It is postulated that the reaction proceeds via an initial alpha-arylation of the vinyl ethers to give labile aryl vinyl ether intermediates, which undergo subsequent ketalization in presence of protons in the reaction media. The method merits attention due to the simplicity of the experimental procedure and the possibility of selective ketal formation in the presence of an additional carbonyl group.