Asymmetric Hydrovinylation and Hydrogenation with Metal Complexes of C3‐Symmetric Tris‐Binaphthyl Monophosphites. Issue 6 (8th January 2014)

• Record Type: Journal Article
• Authors: Carrilho, Rui M. B.; Costa, Gonçalo N.; Neves, Ângela C. B.; Pereira, Mariette M.; Grabulosa, Arnald; Bayón, J. Carles; Rocamora, Mercè; Muller, Guillermo
• Is Part Of: European journal of inorganic chemistry. Issue 6(2014)
• Page Start: 1034
• Page End: 1041
• Publication Date: 2014-01-08
• Subjects: Homogeneous catalysis -- Hydrogenation -- Hydrovinylation -- P ligands -- Palladium -- Rhodium; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201301368
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Neutral allyl–palladium complexes stabilised by bulky tris‐binaphthyl monophosphite ligands have been prepared and fully characterised in solution by NMR spectroscopy, which evidenced a dynamic equilibrium between two diastereomeric species. The new allyl–palladium phosphite complexes have been evaluated as catalytic precursors in the asymmetric hydrovinylation of styrene; they show moderate activity and good to excellent chemo‐ and enantioselectivity depending on the substituent at the ligand 2′‐binaphthyl position. Remarkably, the palladium complex bearing the ligand with an adamantyl ester substituent led to 92 % ee toward ( R )‐3‐phenyl‐1‐butene, which suggests that the ester functionality might provide a secondary hemilabile interaction with the metal, thus favouring the enantioselectivity control. Rhodium(I) complexes formed in situ with the same ligands were further applied in the hydrogenation of dimethyl itaconate, but gave limited activity. The best enantioselectivity (62 %) was achieved with the same ligand that contained the adamantyl ester substituent. Abstract : Bulky C 3 ‐symmetric chiral tris‐naphthyl monophosphite ligands have been tested in Pd‐catalysed asymmetric hydrovinylation of styrene, giving in some cases very chemo‐ and enantioselective systems. The same ligands have been used in Rh‐catalysed asymmetric hydrogenation of dimethyl itaconate.