Optically Active 1,2-Bis(1-arylhydroxymethyl) Ferrocene:  A New, Efficient Chiral Ligand for Scandium-Catalyzed Asymmetric Diels−Alder Reaction

Abstract

[reaction: see text] The Sc(OTf)3/FERRODIOL (2) complex was prepared at -78 degrees C in CH2Cl2 in the presence of 2,6-lutidine and MS 4A. The chiral scandium Lewis acid-catalyzed asymmetric Diels-Alder reaction of cyclopentadiene (3) with 3-acyloxazolidin-2-ones (4) effectively produced the adduct (5) in a high yield with good selectivity, i.e., endo/exo = 90:10 up to 91% ee (endo).