Atom economy. Palladium-catalyzed formation of coumarins by addition of phenols and alkynoates via a net CH insertion
BM Trost, FD Toste, K Greenman
Index: Trost, Barry M.; Toste, F. Dean; Greenman, Kevin Journal of the American Chemical Society, 2003 , vol. 125, # 15 p. 4518 - 4526
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Citation Number: 172
Abstract
A strategy to achieve ortho substitution of phenols initiated by an ortho-palladation to create coumarins was examined. Indeed, treatment of alkynoates with electron-rich phenols in the presence of a palladium catalyst and an acid does generate coumarins. The scope of the reaction with respect to the phenol and the alkynoates is defined. With unsymmetrical aromatic substrates, generally good regioselectivity that reflects the HOMO coefficients ...