Synthetic studies on terpenoids. part 21. Synthesis of a few perhydro-phenanthrene derivatives related to cheilanthatriol and its degradation products

Stereospecific syntheses of 10α-hydroxy-1,1,4aβ,8aβ-tetramethyl-trans-transoid-trans-2,3,4,a,4b,5,7,8,8a,9,-10,10a-dodecahydrophenanthren-6(1H)-one (9) and 1,1,4aβ,8aβ-tetramethyl-8β-(3-methylpentanoyl)-2,3,4,4a,-4b,5,7,8,8a,9-decahydrophenanthren-6(1H)-one (15), potential intermediates for cheilanthatriol, are described. A few related transformations examined during these studies are discussed