Sequential directed ortho metalation-boronic acid cross-coupling reactions. A general regiospecific route to oxygenated dibenzo [b, d] pyran-6-ones related to ellagic …

…, A Kandil, PA Patil, MJ Sharp, MA Siddiqui…

文献索引：Alo, B. I.; Kandil, A.; Patil, P. A.; Sharp, M. J.; Siddiqui, M. A.; et al. Journal of Organic Chemistry, 1991 , vol. 56, # 12 p. 3763 - 3768

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被引用次数: 197

摘要

A general regiospecific synthesis of dibenzo [b, d] pyran-6-one derivatives la, c and 8a-i related to ellagic acid is described (Scheme I, Table I). The sequence involves directed ortho metalation-boronation of benzamides 4 to give the arylboronic acids 5, which, upon palladium-catalyzed cross-coupling with alkoxybromobenzenes 6 leads to the biphenylamides 7. BBr3 demethylation followed by acid-catalyzed cyclization affords ...