HIGHLY REGIOSELECTIVE HYDROFORMYLATION OF INTERNAL, FUNCTIONALIZED OLEFINS APPLYING PT SN COMPLEXES WITH LARGE BITE ANGLE DIPHOSPHINES/

The regioselective hydroformylation of methyl 3-pentenoate (M3P) leadi ng to linear 5-formyl methyl pentanoate (3-FMP) was studied. For this purpose Pt/Sn catalyst systems were modified by diphosphine ligands de rived from heteroaromatic xanthene-type hydrocarbons. These xantphos l igands possess a large bite angle combined with a rigid backbone. The (P boolean AND P)PtCl2 catalyst precursor complexes were prepared and characterized by H-1- and P-31 NMR-spectroscopy. The catalysts show un precedented high regioselectivity to the terminal aldehyde. In additio n, the undesired hydrogenation of the substrate and the products is la rgely suppressed. It was shown that activity as well as selectivity ar e controlled both by the bite angle and the rigidity of the backbone o f the ligands. (C) 1998 Elsevier Science S.A.