General and efficient route for the synthesis of 3,4-disubstituted coumarins via Pd-catalyzed site-selective cross-coupling reactions

The Pd-catalyzed decoupling reactions which facilitates the synthesis of diversified 3,4-diarylated coumarins is described. The strategy was developed on the basis of different selectivities of 3-bromo-4-trifloxycoumarins and 3-bromo-4-tosyloxycoumarins in Suzuki-Miyaura cross-coupling.