Preparation and application of chiral spiro nitrogen-containing ligands for cobalt-catalyzed asymmetric Michael addition

Two novel chiral spire, nitrogen-containing ligands, 7,7'-bis(2-pyridinecarboxamido)-1,1'-spirobiindane (abbreviated as SIPAD) and 7,7-bis(2-quinolinecarboxamido)-1,1'-spirobiindane (abbreviated as SIQAD), were conveniently prepared from 1,1'-spirobiindane-7,7'-dicarboxylic acid in high yields (85% and 84%, respectively) in two steps. The cobalt complexes prepared in situ from Co(OAc)(2) and the ligands have been proven to be efficient catalysts for the asymmetric Michael addition reaction of malonates to chalcone derivatives. The alkylation products were obtained in high yields with moderate enantiomeric excesses under mild reaction conditions. (c) 2006 Elsevier Ltd. All rights reserved.