A thermodynamic preference of chiral cis-γ,δ-epimino-(E)-α,β-unsaturated esters over other stereoisomers: Synthetically useful Pd(0)-catalyzed equilibrated reactions of aziridines bearing an α,β-unsaturated ester group
A practical synthesis of chiral N-arylsulfonyl-cis-γ,δ-epimino-(E)-α,β-enoates, key intermediates for the synthesis of (E)-alkene dipeptide isosteres via Pd(0)-catalyzedequilibratedreactions, has been successfully achieved by exposing N-arylsulfonyl-γ,δ-epimino-α,β-unsaturatedesters to a catalytic amount of Pd(PPh3)4 in THF at 0 ∼ 20 °C.