LAUSR

Abstract Herein, the independent differential selectivity in the Suzuki-Miyaura reaction of two competing arylboronic acids with regard to the nature of the aryl halide (both halide and aryl moieties) was established. This pattern cannot be realized via the “textbook” mechanism of the reaction, which suggests the interaction of boron-containing species with an ArPdX intermediate (product of the aryl halide catalytic activation). The data obtained indicate the participation of two distinct palladium species in the aryl halide and arylboronic acid activations in the catalytic cycle of biaryl formation, which are in accordance with the so-called cooperative mechanism.