Spiro[bicyclo[5.1.0]octane-4,1'-cyclopentan]-3-one,4'-(1,3-dioxolan-2-yl)-2'-ethenyl-2-[2-[[(4-methoxyphenyl)methoxy]methyl]-2-propenyl]-5,8,8-trimethyl-, (1R,1'R,2S,2'S,4'S,5R,7R)-