Bicyclo[7.2.0]undec-4-en-3-one,4-[[[(1S,5R,- 9R)-10,10-dimethyl-2,6-bis(methylene)-7- oxobicyclo[7.2.0]undec-5-yl]oxy]methyl]-11,11- dimethyl-8-methylene-,(1R,4E,9S)-