CHIRAL ORGANOSULFUR COMPOUNDS VII - CHIRAL SULFOXIDE LIGANDS BEARING NITROGEN-ATOMS AS STEREOCONTROLLABLE COORDINATING ELEMENTS IN PALLADIUM-CATALYZED ASYMMETRIC ALLYLIC ALKYLATIONS

Palladium-catalyzed asymmetric allylic alkylations were studied by usi ng chiral sulfoxide ligands bearing nitrogen atoms as coordinating ele ments, such as chiral alpha-sulfinylacetamides, beta or gamma-amino su lfoxides, and beta-sulfinyl sulfonamides. The effects of the chiral su lfinyl functions on the asymmetric induction were demonstrated. Use of (S)-2-pyrrolidinophenyl p-tolyl sulfoxide or (S)-2-(N-butyI-N-methyla minomethyl)phenyl p-tolyl sulfoxide as chiral ligands in the palladium -catalyzed asymmetric allylic alkylations provided the highest enantio selectivity (50 or 58% e.e., respectively) among chiral sulfoxide liga nds examined by us. The participation of the sulfinyl groups in these catalytic asymmetric reactions is rationalized, and the mechanism for the asymmetric induction is proposed on the basis of the stereochemica l outcome obtained. (C) 1998 Elsevier Science Ltd. All rights reserved .