Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline-a Ligand with Wide Substrate Scope

Identifier:  PC:1537

Handle: https://hdl.handle.net/20.500.11797/PC1537

Authors:  Maria Biosca; Rosalba Bellini; Marc Magre; Per-Ola Norrby; Oscar Pàmies; Montserrat Diéguez; Christina Moberg

Abstract:
Excellent enantioselectivities are observed in palladium-catalyzed allylic substitutions of a wide range of substrate types and nucleophiles using a bidentate ligand composed of oxazoline and chirally flexible biaryl phosphite elements. This unusually wide substrate scope is shown by experimental and theoretical studies of its ¿3-allyl and ¿2-olefin complexes not to be a result of configurational interconversion of the biaryl unit, since the ligand in all reactions adopts an Sa,S configuration on coordination to palladium, but rather the ability of the ligand to adapt the size of the substrate-binding pocket to the reacting substrate. This ability also serves as an explanation to its excellent performance in other types of catalytic processes.