Highly enantioselective copper-catalyzed conjugate addition of diethylzinc to enones using chiral spiro phosphoramidites as ligands.

Abstract

Novel monodentate chiral spiro phosphoramidite ligands have been readily synthesized in good yields from enantiomerically pure 1,1'-spirobiindane-7,7'-diol. The new ligands were highly efficient in the copper-catalyzed conjugate addition of Et(2)Zn to enones with up to 98% enantiomeric excess.