You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named tert-butyl (6'R)-6',12'-dimethyl-9'-methylidene-7'-oxospiro[1,3-dioxolane-2,4'-8-azatricyclo[4.3.3.01,5]dodecane]-8'-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C21H31NO5
assistant