Influence of 1,4-Bis(diphenylphosphino)butane on the Hydroformylation of α,β-Unsaturated Esters Catalyzed by Zwitterionic, Cationic, and Neutral Rhodium(I) Complexes. The Asymmetric Hydroformylation od α-Methylene-γ-Butyrolactone

Article abstract of DOI:10.1021/jo00108a007

An investigation was made of the effect of 1,4-bis(diphenylphosphino)butane (dppb) on the regioselectivity of the hydroformylation of α,β-unsaturated esters with synthesis gas, catalyzed by rhodium(I) complexes.Excellent regioselectivity was obtained when dppb was added as a ligand for the reaction of methyl acrylate and α-methylene-γ-butyrolactone with synthesis gas.However, it inhibits the reaction when methyl methacrylate is used as the substrate.The asymmetric hydroformylation of α-methylene-γ-butyrolactone using (+)Cl(-) as the catalyst and (R)-BINAP as the chiral ligand (6:1 ratio of (R)-BINAP/Rh) gave an aldehydic lactone, containing a quaternary chiral center, in up to 37percent ee.