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 methyl (2R,3aS,6R,6aR)-2-ethenyl-6a-(2-methoxy-2-oxoethyl)-5-[(4-methoxyphenyl)methyl]-4-oxo-2,3,3a,6-tetrahydrofuro[2,3-c]pyrrole-6-carboxylate .
user
C21H25NO7
assistant