Effects of the electronic properties of chiral chelating diphosphines in stereoselective Diels-Alder cycloaddition reactions promoted by their transition metals complexes

摘要

The Pd(II) and Pt(II) complexes (perchlorates and hexafluoroantimoniates, respectively) of a series of C-2 symmetric biheteroaromatic diphosphines differing in their electronic properties at phosphorus have been tested as catalysts in [4 + 2]-cycloaddition reactions of cyclopentadiene and N-2-alkenoyl-1,3-oxazolidine-2-ones. The best stereoselection results were obtained with the complexes produced from electron-rich ligands, which were found to give also the kinetically most active catalysts. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 21]