succinic acid allyl ester 2-(4-allyloxycarbonyl-3-methyl-buta-1,3-dienyl)-3-butyl-8-[6-(tert-butyl-dimethyl-silanyloxy)-3,7-dimethyl-8-triethylsilanyloxy-octa-2,4-dienyl]-9-methyl-1,7-dioxa-spiro[5.5]undec-3-yl ester