Bismuth(III) triflate catalyzed tandem esterification–Fries–oxa-Michael route to 4-chromanones
作者:Kevin Meraz、Krishna Kumar Gnanasekaran、Rup Thing、Richard A. Bunce
DOI:10.1016/j.tetlet.2016.10.005
日期:2016.11
An efficient tandem reaction approach is described to prepare 4-chromanones from electron-rich phenols and 3,3-dimethylacrylic acid or trans-crotonic acid in boiling toluene using 20 mol % bismuth(III) triflate as the catalyst. The reaction is also successful from the corresponding aryl esters of each of these acids under the same conditions. The procedure is convenient to perform, and 25–90% yields