Abstract
A synthesis of a perhydrobenzo[a]xanthene related to the skeleton of siccanin (3), an antifungal antibiotic, was described. A series of reactions starting from Δ1(9)-octal-2-one (5) gave 1-(2-hydroxy-6-methoxy-4-methylbenzyl)-2-methylene-9-vinyl-cis-decalin (19), whose acid-catalysed cyclization reaction yielded a perhydrobenzo[a]xanthene (20a) with cis/anti/cis ring junctures. The structure of the latter compound was determined by three dimensional X-ray analysis of its brosyl derivative (20c)
