Syntheses and applications of 2-phosphino-2'-alkoxy-1,1'-binaphthyl ligands. Development of a working model for asymmetric induction in hydrovinylation reactions

Among the handful of monophosphine ligands that effect asymmetric hydrovinylation of vinylarenes, 2-diphenylphosphino-2'-methoxy-1,1'-binaphthyl MOP) is among the most accessible. Addition of a methyl group at the 3'-position of this ligand significantly improves the enantioselectivity of hydrovinylation of prototypical alkenes. Introduction of a chiral phospholane at the C-2 position of this scaffolding has no effect on the enantioselectivity. These results are consistent with a model proposed for the asymmetric induction for this exacting reaction.