Insight into the Course of the Ferrier Rearrangement Used to Obtain Untypical Diosgenyl Saponins
Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The Ferrier rearrangement was utilized to obtain 2,3-unsaturated diosgenyl glycosides. This reaction proceeded with high stereoselectivity, yielding mostly saponins with an α configuration (hexoses) or predominantly with a β configuration (pentoses). The diversity of the glycals used and the glycosides obtained enabled a deep discussion of the Ferrier rearrangement mechanism. The mechanism was supported by DFT calculations concerning the intermediate ions. It was concluded that the vinylogous anomeric effect may influence the reactivity of the glycals. Two possible Ferrier rearrangement intermediates, dioxolenium and allyloxycarbenium ions, were hypothesized to exist in thermodynamic equilibrium that shifted toward the former. The allyloxycarbenium ion participates in the final rearrangement step and determines the reaction regioselectivity. Furthermore, the conformational stability of the 2,3-unsaturated pyranose ring determines the stereoselectivity of the reaction. Factors influencing this stability, as well as the NMR data enabling recognition of the 0 H 5 and 5 H 0 conformations, were identified. Chemoselective hydrogenation of 2,3-unsaturated diosgenyl glycosides provided a series of 2,3-dideoxy analogues. The anticancer, hemolytic, and antibacterial activities of the synthesized saponins are presented alongside a discussion of the structure–activity relationships.
Source: The Journal of Organic Chemistry
Institutions: University of Gdańsk, Gdańsk Medical University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4403147095