Asymmetric Reactions of Enamines with Methyl (<i>E</i>)-4-Oxo-4-(2-oxo-1,3-oxazolidin-3-yl)-2-butenoate by the Use of a Chiral Titanium Reagent

Abstract

Abstract Asymmetric Michael and [2+2] cycloaddition reactions between enamines and methyl (E)-4-oxo-4-(2-oxo-1,3-oxazolidin-3-yl)-2-butenoate proceed with a chiral titanium reagent generated in situ from dichlorodiisopropoxytitanium and a tartrate-derived chiral 1,4-diol. In the presence of excess amounts of the chiral titanium reagent, good to moderate enantioselectivity is attained. The reactions are also well catalyzed even with a catalytic amount of the titanium reagent.