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.