Synthesis of a Novel Unsymmetrical Bisoxazoline Ligand with sp² Bridging Carbon

Abstract

A novel unsymmetrical bisoxazoline ligand was synthesized in one step by the Knoevenagel condensation of aldehydes with a C 2 -symmetric indane-derived bisoxazoline having two acidic hydrogens connected to the bridging carbon. The electronic properties of incorporated bridge substituent due to π-π conjugation with oxazoline rings can affect the catalytic performance of the ligand in asymmetric syntheses, as was shown for the Henry reaction between benzaldehyde and nitromethane.