Question about Sigma Tc-2001

I see from the Canon website that this lens is not compatible with the Canon extender. So I assume that the Sigma converter will not fit either.
I own an older Canon lens (EF 75-300 1:4-5.6 USM). Here it is the case that it cannot be coupled mechanically. This is because the extender lens protrudes beyond the body and the rearmost lens of the lens is at the same height as the mount.

I tried it once with the Canon EF 100-400mm f/4.5-5.6L IS USM: Mechanically, the converter fitted the lens, but the autofocus and aperture control no longer worked. I assume that this is the same with the 70-300.