Organocatalytic Regio- and Enantioselective [3 + 2]-Annulations of Ninhydrin-Derived Morita-Baylis-Hillman Carbonates with 3-Methyleneoxindoles

J Org Chem. 2022 Mar 4;87(5):3184-3194. doi: 10.1021/acs.joc.1c02917. Epub 2022 Feb 8.

Abstract

A type of Morita-Baylis-Hillman (MBH) carbonates has been developed from ninhydrin. These MBH carbonates have been successfully employed as 3C-synthons in the organocatalytic asymmetric [3 + 2]-annulations of the isatin-derived electron-deficient olefins, affording structurally diverse spirooxindoles in high yield with excellent stereoselectivity. In particular, the regioselectivity of MBH carbonates was controlled by the reaction partner, 3-methyleneoxindoles with carbonyl groups (R = ArCO), affording β-selective products and 3-methyleneoxindoles with ester groups (R = CO2Me) furnishing γ-selective products. The representative scale-up reactions and transformation of product were examined. The reaction mechanism was expounded by control experiments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbonates
  • Catalysis
  • Isatin*
  • Ninhydrin*
  • Stereoisomerism

Substances

  • Carbonates
  • Isatin
  • Ninhydrin