A New Diphosphite Promoting Highly Regioselective Rhodium-Catalyzed Hydroformylation

A new rhodium catalyst is described that gives 99% regioselectivity in linear aldehyde in the hydroformylation of internal and terminal olefins. High-pressure NMR spectroscopic data verify an energetically preferred bis-equatorial mode of coordination for the bidentate phosphite ligand in the hydride resting state of the catalyst. Experimental FTIR spectra are compared with the individual spectra of the e, e and e, a isomers of [HRh(CO) 2 (P∩P)] calculated from density functional theory.