File: Save As
And Pick Catia5 Fromat from the pulldown at the bottom.
Or, do you want to open native Inventor files in Catia, if so you might want to visit the Catia Forum.
T.S.
I believe that CATIA V5 was released in 2013. When you encounter software of the same year release it's tough for the other software mfg'rs to know what changes the other software mfg'rs are going to make to their software.
You will most likely have to export out to a neutral format such as IGES or STEP.