Asymmetric Synthesis via chiral pi-Allyl- palladium complexes

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We have found the first example of the palladium-catalyzed asymmetric allylations of chiral enamines, imines, and hydrazones derived from readily obtainable optically active alpha-amino acid allyl esters such as (S)-proline and (S)-valine derivatives.Chiral enamines or hydrazones having phosphine groups, which was derived from (S)-proline derivatives, represented high enantioselectivity in the palladium-catalyzed allylations, in which the phosphine groups served as intramolecular chiral ligands and the great stereoelectronic effects of the anionic counterparts of the allylating reagents on the asymmetric induction were observed.Chiral enamines bearing allylating parts underwent intramolecular asymmetric allylations under palladium-catalyzed reaction conditions, affording optically active cyclic compounds. this novel method for asymmetric carbon-carbon bond formations was applied to the synthesis of optically active natural products such as indole alkaloids and monoterpenes.