1-METHYL-2-VINYLPYRROLE AND 1-PHENYL-3,4-DIMETHYLPHOSPHOLE - THEIR COORDINATION CHEMISTRIES AND REACTIVITIES IN A CHIRAL PALLADIUM COMPLEX PROMOTED ASYMMETRIC DIELS-ALDER REACTION

Coordinated 1-phenyl-3,4-dimethylphosphole in the chiral complex oro{( S)-1-[1-(dimethylamino)ethyl]-naphthylC(2),N} [1-phenyl-3,4-dimethylph osphole-P]palladium behaves as an activated cyclic diene in the interm olecular Diels-Alder reaction with 1-methyl-2-vinylpyrrole to give a p air of diastereomeric P-chiral endo-cycloadducts. The diastereomeric p alladium complexes could be separated by fractional crystallization an d the enantiomerically pure phosphanorbornene ligands could be liberat ed individually from the complexes by treatment with potassium cyanide . In contrast, the [4+2] cycloaddition reaction did not occurred under similar conditions when the chloro ligand in the phosphole complex wa s replaced with a perchlorato ligand. (C) 1998 Elsevier Science Ltd. A ll rights reserved.