No abstract

No abstract

No abstract

No abstract

The first total synthesis of (+)-griseusin A (2) has been achieved. The properly functionalized 1,4,5-trihydroxynaphthalene derivative 9 prepared from 3-bromojuglone (7) via 2-allylation with 3-butenoic acid was successively treated with -BuLi and L-dideoxygulose derivative 4 to give the carbinol 10. The corresponding ketone 11 obtained by PCC oxidation was transformed to bromo spiro ketals 12a,b by reaction with aqueous iV-bromoacetamide followed by acid-catalyzed intramolecular ketalization. Reaction of 12a,b with NaCN and hydrolysis of the resulting nitriles 13 provided a single carboxylic acid, 14, from which (H-)-griseusin B (16) was obtained by three steps: O-acetylation, removal of the methoxymethyl group, and AgO oxidation. Finally, (+)-griseusin A, an enantiomer of naturally occurring griseusin A, was obtained by known aerial oxidation in pyridine.