Diastereoselective [3+1] Cyclization Reaction of Oxindolyl Azaoxyallyl Cations with Sulfur Ylides: Assembly of 3,3'-Spiro[β-lactam]-oxindoles

Oxindoles and beta-lactams are attractive structural motifs because of their unique biological importance. However, the fusion of the two moieties featuring 3,3'-spirocyclic scaffolds is a challenging task in organic synthesis. Herein we designed a novel type of oxindole-based azaoxyallyl cation synthons, which could readily participate in the [3 + 1] cyclization with sulfur ylides. With this protocol, a collection of 3,3-spiro[beta-lactam]-oxindoles were facilely produced in up to 94% yield with perfect diastereoselectivity.

Automated summary

A novel oxindole-based azaoxyallyl cation synthons were designed for [3+1] cyclization with sulfur ylides, leading to facile production of 3,3-spiro[beta-lactam]-oxindoles with up to 94% yield and perfect diastereoselectivity.