You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 4-[[(3R,4S,5R,6R)-5-methoxy-4-[(2R,3R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl]-1-oxaspiro[2.5]octan-6-yl]oxycarbonylamino]-3-methylbutanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H37NO7
assistant