AbstractA metal‐free intramolecular annulation of 2‐aryloxybenzaldehydes to xanthones is disclosed, which proceeds through the direct oxidative coupling of an aldehyde CH bond and aromatic CH bonds using tetrabutylammonium bromide (TBAB) as a promoter in aqueous medium. This strategy works smoothly in the presence of both electron‐donating and electron‐withdrawing groups, and displays good tolerance towards catalytically reactive substituents, thus promising further functionalizations of xanthone products.magnified image
Rhodium-Catalyzed Xanthone Formation from 2-Aryloxybenzaldehydes via Cross-Dehydrogenative Coupling (CDC)
作者:Ping Wang、Honghua Rao、Ruimao Hua、Chao-Jun Li
DOI:10.1021/ol203381q
日期:2012.2.3
A concise and straightforward strategy to construct a xanthone skeleton via an intramolecular cross-dehydrogenative coupling (CDC) of 2-aryloxybenzaldehydes has been developed. The reaction proceeded smoothly without any need of preactivation of the aldehyde group. It can tolerate various functional groups and provides an applicable protocol to construct a wide range of xanthone derivatives.