Formal total synthesis of (+)-diepoxin sigma.
The highly oxygenated antifungal anticancer natural product (+/-)-diepoxin sigma was prepared in 10 steps and in 15% overall yield from O-methylnaphthazarin. Highlights of the synthetic work include an Ullmann coupling and a possibly biomimetic oxidative spirocyclization for the introduction of the naphthalene ketal as well as the use of a retro-Diels-Alder reaction to unmask the reactive enone moiety in the naphthoquinone bisepoxide ring system. A novel highly bulky chiral binaphthol ligand was developed for a boron-mediated Diels-Alder reaction that constitutes a formal asymmetric total synthesis of (+)-diepoxin sigma.
Wipf
P
P
Department of Chemistry, University of Pittsburgh, Pennsylvania 15260, USA. pwipf+@pitt.edu
Jung
J K
JK
D000349:Africa; D018360:Crystallography, X-Ray; D004852:Epoxy Compounds / Q000138:chemical synthesis*; D010946:Plants, Medicinal / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis*
D004852:Epoxy Compounds; D013141:Spiro Compounds; C089783:diepoxin sigma