Highly Enantioselective Construction of Spirocyclopentaneoxindoles Containing Four Consecutive Stereocenters through an Organocatalytic Iminium-Enamine Cascade Reaction

Spirocyclopentaneoxindole derivatives containing four consecutive stereocenters, including a spiro quaternary center, were constructed by an organocatalytic iminium-enamine cascade sequence in good yields (up to 86%) with excellent enantiomeric (up to >99% ee) and diastereomeric purities (up to >99:1dr). This highly efficient procedure will allow diversity-oriented syntheses of this intriguing class of compounds with potential biological activities.