New Rigid Polycyclic Bis(phosphane) for Asymmetric Catalysis.

Affiliation

Faculty of Chemistry, Maria Curie-Sklodowska University, 33-Gliniana St., 20-031 Lublin, Poland. [Email]

Abstract

A simple, highly efficient synthesis of a series of novel chiral non-racemic rigid tetracyclic phosphorus ligands, applicable in important chemical asymmetric transformations, was performed. In a tandem cross-coupling/C-H bond activation reaction, a well-recognised and readily available ligand (R,R)-NORPHOS was used as the starting material. The palladium complexes of new ligands were obtained and characterised on the example of a crystalline dichloropalladium complex of [(1R,2R,9S,10S,11R,12R)-4-phenyltetracyclo[8.2.1.02,9.03,8]trideca-3,5,7-triene-11,12-diyl]bis(diphenylphosphane). A notably high activity and stereoselectivity of the palladium catalysts based on the new ligands were confirmed in a model asymmetric allylic substitution reaction. Herein, we discuss the geometry of the palladium complexes formed and its impact on the efficiency of the catalysts. A comparison of their geometric features with other bis(phosphane) ligand complexes found in the Cambridge Structural Database and built density functional theory (DFT) commutated models is also presented and rationalised.

Keywords

C-H bond activation,DFT calculations,NORPHOS,allylic alkylation,asymmetric catalysis,bis(phosphane) palladium complex,chiral phosphines,metallacycle,polycyclic compounds,stereoselective synthesis,

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