Olefin Hydrogenation with Rigid Mono-P-stereogenic Diphosphines: A Flexible Rhodium Ring to Rule Them All?

The preparation of a rigid C-1-symmetric P-stereogenic diphosphine series possessing a P-o-diphenylphosphinophenyl moiety and its use in Rh-I-catalyzed hydrogenation of benchmark olefins, is presented. This simplified ligand design, wherein some specific features (backbone flexibility, identical nature of P,P-substituents) of related C-2-symmetric ethylene-bridged diphosphines were knocked out, is a useful study-tool with which to better understand the role of essential motifs that guide catalysis in the original model.