Total synthesis of (+/-)-phomactin G, a platelet activating factor antagonist from the marine fungus Phoma sp.
A total synthesis of phomactin G (), which is a central intermediate in the biosynthesis of phomactin A () in Phoma sp. is described. The synthesis is based on a Cr(ii)/Ni(ii) macrocyclisation from the aldehyde vinyl iodide, leading to, followed by sequential conversion of into the [small beta]-epoxide and the ketone which, on deprotection, led to (+/-)-phomactin G. Phomactin G () shares an interesting structural homology with phomactin D (), the most potent PAF-antagonist metabolite in Phoma sp. It is most likely converted into phomactin A (), by initial allylic oxidation to the transient [small alpha]-alcohol 'phomactin' structure, known as Sch 49028, followed by spontaneous pyran ring formation.
Goldring
William P D
WP
School of Chemistry, The University of Nottingham, University Park, Nottingham, UK.
Pattenden
Gerald
G
D001203:Ascomycota / Q000737:chemistry*; D004852:Epoxy Compounds / Q000138:chemical synthesis*; D015394:Molecular Structure; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors*
D004852:Epoxy Compounds; D010972:Platelet Activating Factor; C096983:phomactin G