...
Even with the release of ChemDraw version 16 from PerkinElmer Informatics, round trip editing using the common drag and drop method still does not work with Office 2016 (although compatibility with Office 2011 continues). With the end of the support lifecycle for Office 2011 on 10/10/2017, it may no longer be possible to install Office 2011 on newer versions of macOS. There is currently a workaround for this problem which is using copy (⌘+C) and Paste as PDF (⌘+Control+V) instead of drag and drop in Office 2016.
What you need to know: Mac's MS Office and ChemDraw
...