Hydrogen Bond Assisted Central-to-Spiro Chirality Transfer and Central-to-Axial Chirality Conversion: Asymmetric Synthesis of Spirocycles.

The asymmetric construction of chiral spiroenones bearing both axial and spiro-central chirality has been established for the first time by a central-to-spiro chirality transfer and a central-to-axial chirality conversion from chiral 2,3-diarylbenzoindolines. Mechanistic studies indicate the hydrogen bonds play important roles in this process, providing an efficient strategy for enantioselective construction of spirocyclic backbones via simultaneously controlling spiro-central and axial chirality in one operation.