(1R,3R,5S,8S)-3-(tert-butyldimethylsilyloxy)-8-methyl-2-methylene-8-vinyl-6-oxabicyclo[3.2.1]octan-7-one

(1S,3R,5S,8R)-3-(tert-butyldimethylsilyloxy)-8-hydroxymethyl-8-methyl-2-methylene-6-oxabicyclo[3.2.1]octan-7-one

(3S,4S,5R,6S,8R)-5-benzyloxymethyl-8-(tert-butyldimethylsilyloxy)-5-methyl-4-vinyl-1-oxaspiro[2.5]octan-6-ol

(3S,4S,5R,6S,8R)-5-benzyloxymethyl-8-(tert-butyldimethylsilyloxy)-5-methyl-1-oxaspiro[2.5]octane-4,6-carbolactone

(3S,4S,5R,6S,8R)-5-benzyloxymethyl-8-(tert-butyldimethylsilyloxy)-5-methyl-4-vinyl-1-oxaspiro[2.5]octan-6-yl benzoate