PyBidine–Ni(OAc)2‑Catalyzed Michael/Aldol Reaction of Methyleneindolinones and Thiosalicylaldehydes for Stereochemically Divergent Thiochromanyl-spirooxindoles

(S,S)-Diphenylethylenediamine-derived bis­(imidazolidine)­pyridine (PyBidine)–Ni­(OAc)2 complex catalyzed the asymmetric Michael/aldol reaction of methyleneindolinone and thiosalicylaldehyde to produce (2′R,3S,4′R)-thiochromanyl-spirooxindole having three contiguous stereogenic centers.