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,3'R,4S,5S)-1'-benzyl-3'-prop-2-enylsulfanylspiro[7-oxabicyclo[2.2.1]hept-2-ene-5,4'-azetidine]-2'-one .
user
C18H19NO2S
assistant