Total Synthesis of (−)-Glionitrin A and B Enabled by an Asymmetric Oxidative Sulfenylation of Triketopiperazines

Asymmetric construction
of dithiodiketopiperazines on otherwise
achiral scaffolds remains a pivotal synthetic challenge encountered
in many biologically significant natural products. Herein, we report
the first total syntheses of (−)-glionitrin A/B and revise
the absolute configurations. Emerging from the study is a novel oxidative
sulfenylation of triketopiperazines that enables asymmetric formation
of dithiodiketo­piperazines on sensitive substrates. The concise
route paves the way for further studies on the potent antimicrobial
and antitumor activities of glionitrin A and the intriguing ability
of glionitrin B to inhibit invasive ability of cancer cells.