Total synthesis of the proposed structures of gladiosides I and II

Burkholderia gladioli is a Gram-negative bacterium that biosynthesizes a cocktail of potent antimicrobial compounds, including the antifungal phenolic glycoside sinapigladioside. Herein, we report the total synthesis of the proposed structures of gladiosides I and II, two structurally related phenolic glycosides previously isolated from B. gladioli OR1 cultures. Importantly, the physical and analytical data of the synthetic compounds were in significant discrepancies with the natural products suggesting a misassignment of the originally proposed structures. Furthermore, we have uncovered an acid-catalyzed fragmentation mechanism converting the alpha,beta-unsaturated methyl carbamate-containing gladioside II into the aldehyde-containing gladioside I. Our results lay the foundation for the expeditious synthesis of derivatives of these Burkholderia-derived phenolic glycosides, which would enable to decipher their biological roles and potential pharmacological properties.

Automated summary

The study reported the total synthesis of two proposed structures of gladiosides I and II derived from Burkholderia gladioli, revealing significant discrepancies between the synthetic compounds and the natural products, indicating a possible misassignment of the originally proposed structures. Additionally, an acid-catalyzed fragmentation mechanism was uncovered.