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Brønsted Acid Catalyzed Enantioselective Assembly of Spirochroman-3,3-oxindoles.

Alavala Gopi Krishna ReddyPedireddi NiharikaSu ZhouShi-Kun JiaTaoda ShiXinfang XuYu QianWenhao Hu
Published in: Organic letters (2020)
An enantioselective cyclization of diazoindolinones with o-hydroxymethyl chalcones has been established by a cooperative dirhodium complex and chiral phosphonic acid catalysis under mild conditions. This reaction is the first example of catalytic asymmetric intramolecular Michael-type trapping of oxonium ylide enabled by phosphoric acid through a dual H-bonding activation model, which provides an efficient access to the chiral spirochroman-3,3-oxindoles, with vicinal quaternary and tertiary stereocenters, in good to excellent yields and enantioselectivities.
Keyphrases
  • ionic liquid
  • room temperature
  • crystal structure
  • electron transfer