Design, Synthesis and Resolution of Spirocyclic Bisoxindoles Based C2-Symmetric Diols.

A new type of spirocyclic bisoxindole-based C-2-symmetric diols (SBIDOLs) was designed and synthesized. A series of racemic SBIDOL derivatives (6a-6g) were readily synthesized from commercially available 2-halo-S-methoxyanilines 1 (X = Cl or Br) through N-mono alkylation, acylation, oxidation, double intramolecular Friedel-Crafts reaction, and demethylation reactions. The optical resolution of racemic 6b was achieved via fractional crystallization of their bis-L-menthoxycarboxylates. Further modifications of SBIDOLs were investigated, leading to 5,5'-diaryl SBIDOL derivatives (11a and 11b) through Pd-catalyzed Suzuki coupling and DM-SBIDOL 12 by Pd/C-catalyzed hydrogenative dechlorination reactions.