Asymmetric Michael Addition of Chiral Lithiated Sulfonates to Nitroalkenes: Diastereo- and Enantioselective Synthesis of α,β-Disubstituted γ-Nitro and β-Alkoxycarbonyl Methyl Sulfonates

Abstract

The diastereoselective Michael addition of lithiated enantiopure sulfonates to nitroalkenes is described. High asymmetric inductions were obtained by using 1,2:5,6-di-O-isopropylidene-α-d-allofuranose as a cheap and easily available chiral auxiliary. Racemization-free cleavage of the auxiliary led to α,β-disubstituted γ-nitro methyl sulfonates. A change of the cleavage conditions resulted in α,β-disubstituted β-alkoxycarbonyl sulfonates via the Meyer reaction (de ≥ 98%, ee ≥ 98%).