You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (1S,2S,4S,4'S,6R,7S,8R)-4'-ethenyl-4',11-dimethyl-2-phenyl-8-prop-1-en-2-ylspiro[3-oxatricyclo[5.4.0.02,6]undec-10-ene-4,3'-oxolane]-2',5-dione .
user
C26H28O4
assistant