Export Table of Contents from PDF into Omnioutliner


I have severel PDF-Documents with table of contents (may levels), but they are only visible in the sidebar of PDF-Expert / Preview from mac. I am searching for a way of exporting these table of contents into Omnioutliner as I want to make further adjustments to them/ work independently with them. I tried selecting all the TOCs in the sidebar of PDF-Expert, I can drag them out but I am not able to drop them into Omnioutliner or into Word or anyother word processing app. Does anybody has an idea?

Thank you!