Isothiourea-Catalyzed [2 + 2] Cycloaddition of C(1)-Ammonium Enolates and N -Alkyl Isatins.
Yusra AbdelhamidKevin KastenJoanne DunneWill C HartleyClaire M YoungDavid Bradford CordesAlexandra M Z SlawinSean NgAndrew David SmithPublished in: Organic letters (2022)
Enantioselective [2 + 2] cycloaddition of C(1)-ammonium enolates generated catalytically using the isothiourea HyperBTM with N -alkyl isatins gives spirocyclic β-lactones. In situ ring opening with an amine nucleophile generates isolable highly enantioenriched products in up to 92:8 dr and in >99:1 er.