Synthesis of Octahydroperylene, the Framework of Altertoxin III

Routes to the framework of perylenequinone-derived mycotox-
ins of the dihydroanthracene type are described. Starting with
anthracene derivatives, attachment of C3 units at positions 9
and 10 and twofold cyclization would furnish the required
pentacycle. Heck-type couplings, S$_N$2 additions of enolates,
alkynyl and allyl additions turned out to be not successful, while
addition of a Grignard reagent prepared from acetal-protected
3-bromopropionaldehyde to anthraflavic acid methyl ester,
subsequent acetal cleavage, and Birch reduction furnished
octahydroperylene in only four steps.