RESUMO
The precise control of the regioselectivity in the transition metal-catalyzed migratory hydrofunctionalization of alkenes remains a big challenge. With a transient ketimine directing group, the nickel-catalyzed migratory ß-selective hydroarylation and hydroalkenylation of alkenyl ketones has been realized with aryl boronic acids using alkyl halide as the mild hydride source for the first time. The key to this success is the use of a diphosphine ligand, which is capable of the generation of a Ni(II)-H species in the presence of alkyl bromide, and enabling the efficient migratory insertion of alkene into Ni(II)-H species and the sequent rapid chain walking process. The present approach diminishes organosilanes reductant, tolerates a wide array of complex functionalities with excellent regioselective control. Moreover, this catalytic system could also be applied to the migratory hydroarylation of alkenyl azahetereoarenes, thus providing a general approach for the preparation of 1,2-aryl heteroaryl motifs with wide potential applications in pharmaceutical discovery.
RESUMO
The development and the synthetic applications of a novel class of diphosphine ligands (SPSiPs) based on chiral spirosilabiindane diol (SPSiOL) are presented. Starting from SPSiOL, the diphosphine ligands could be readily prepared in three steps with high efficiency. This novel class of diphosphine ligands features rigid configuration, a large dihedral angle, a large P-M-P angle, and a long P-P distance. The potentials of SPSiPs in asymmetric catalysis have also been preliminarily disclosed.