((1R,2R,4aS,8aS)-1,2,4a-Trimethyl-5-oxo-decahydro-naphthalen-1-yl)-acetic acid ethyl ester

ethyl 2-((4aS,5S,8aS)-5,8a-dimethyl-6-methyleneoctahydro-2H-spiro[naphthalene-1,2'-[1,3]dioxolan]-5-yl)acetate

((1R,2R,4aS,8aS)-1,2,4a-Trimethyl-5-trifluoromethanesulfonyloxy-1,2,3,4,4a,7,8,8a-octahydro-naphthalen-1-yl)-acetic acid ethyl ester

ethyl 2-((4aS,5R,6R,8aS)-5,6,8a-trimethyloctahydro-2H-spiro[naphthalene-1,2'-[1,3]dioxolan]-5-yl)acetate

[(1R,2R,4aS,8aS)-5-(tert-Butyl-diphenyl-silanyloxymethyl)-1,2,4a-trimethyl-1,2,3,4,4a,7,8,8a-octahydro-naphthalen-1-yl]-acetic acid ethyl ester