Using various substrates and ligands, we show that electron-deficient, bidentate phosphines are the ligands of choice for palladium-catalyzed arylation of electron-rich olefins. This is in contrast to the reaction of electron-deficient olefins, which benefit from electron-rich monodentate phosphines. A tentative explanation is offered based on DFT calculations.
Highly Regioselective Palladium-Catalyzed Internal Arylation of Allyltrimethylsilane with Aryl Triflates
作者:Kristofer Olofsson、Mats Larhed、Anders Hallberg
DOI:10.1021/jo980249n
日期:1998.7.1
Highly regioselective ligand-controlled Heck-arylation reactions of allyltrimethylsilane, delivering branched beta-products, were performed in moderate to good yields. The high preference for internal over terminal double-bond arylation suggests a contribution from the beta-cation-stabilizing effect of silicon. Microwave-promoted palladium-catalyzed coupling reactions proceeded with the same regioselectivity in six entries out of eight with the reaction times cut sharply down to 5-10 min.