You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3R,3'S)-1',1'-dichloro-3'-ethyl-3-methylspiro[1,3,7,7a-tetrahydropyrrolo[1,2-c][1,3]oxazole-6,2'-cyclopropane]-5-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C11H15Cl2NO2
assistant