Metal-Free Tandem Friedel–Crafts/Lactonization Reaction to Benzofuranones Bearing a Quaternary Center at C3 Position
Long Chen, Feng Zhou, Tao-Da Shi and Jian Zhou*
*Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663 N. Zhongshan Road, Shanghai, 200062, P. R. China, Email: jzhouchem.ecnu.edu.cn
L. Chen, F. Zhou, T.-D. Shi, J. Zhou, J. Org. Chem., 2012, 77, 4354-4362.
DOI: 10.1021/jo300395x (free Supporting Information)
A metal-free tandem Friedel-Crafts/lactonization reaction to 3,3-diaryl or 3-alkyl-3-aryl benzofuranones is catalyzed by HClO4. The reaction of various tertiary α-hydroxy acid esters with substituted phenols affords the desired products in rich diversity. 1H NMR studies supports that this tandem reaction proceeds via tandem Friedel-Crafts/lactonization sequence.
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