Conjugate addition of diethylzinc to chalcones is catalysed by complexes prepared in situ from Ni(acac)(2) and cis-exo-N,N-dialkyl-3-aminoisoborneols or (+)-cis-endo-N,N-dimethyl-3-aminoborneol ((+)- DAB) (13b). The products are obtained with enantioselectivities up to 84 %. When scalemic (-)-cis-exo-N,N-dimethyl-3-aminoisoborneol ((-)-DAIB) (3c) was employed in the reaction a positive nonlinear relationship was found. Several factors which govern catalyst activity and enantioselectivity have been investigated.
|Number of pages||13|
|Publication status||Published - 11-Apr-1994|
- ASYMMETRIC INDUCTION
- ORGANOZINC REAGENTS