Construction of Spirooxindole Skeleton Through Intramolecular Dieckmann Cyclization

Abstract

A highly efficient and direct approach was developed to construct the structurally diverse spirooxindole skeleton, which is an important basic motif in natural products. Both the 3,3′-pyrrolidonyl spirooxindoles and spiroindolin-2-one δ-lactones were smoothly obtained by the intramolecular Dieckmann cyclization of oxindoles in excellent yield under mild conditions.Graphical Abstract

Organocatalytic Asymmetric Michael/Dieckmann Cyclization Reaction of Alkynones To Construct Spirocyclopentene Oxindoles

“…The bifunctional chiral guanidine catalysts, , which have proven particularly effective for the activation of both electrophiles and Michael acceptors, are well suited to a variety of 3-substituted oxindoles and others. We thus wondered whether this approach might be portable to Michael/Dieckmann cyclization between 3-carboxymethyl substituted oxindoles and alkynones. Nevertheless, this asymmetric catalytic cascade reaction is more challenging.…”