摘要 |
Novel catalyst compositions, characterized in that they are based upon a) a palladium compound, b) an acid with a pKa of less than 2, provided that the acid is not a hydrohalogenic acid, c) a bidentate ligand of the general formula R<1>R<2>-M-R-M-R<3>R<4>, wherein M represents phosphorus, arsenic or antimony, R<1>, R<2>, R<3> and R<4> represent hydrocarbyl groups which may or may not be substituted with polar groups and R represents a bivalent organic bridging group having at least two carbon atoms in the bridge, and d) a quinone. |