Cinchona Alkaloid‐Derived Thiourea‐Catalyzed Diastereo‐ and Enantioselective [3+2] Cycloaddition Reaction of Isocyanoacetates to Isatins: A Facile Access to Optically Active Spirooxindole Oxazolines

An efficient diastereo‐ and enantioselective [3+2] cycloaddition reaction of α‐aryl isocyanoacetates to isatins catalyzed by a quinine‐derived bifunctional amine‐thiourea‐bearing sulfonamide as multiple hydrogen‐bonding donor catalyst has been investigated. The corresponding adducts, which bear a spirocyclic quaternary stereocenter at the C‐3 position of the oxindole, were obtained in good yields (51–95%), high diastereoselectivities (up to >20:1 dr) and good to excellent enantioselectivities (up to 97% ee).