Hi Philip:
There is not currently an out-of-the-box way to do this in either ArcGIS Mapping for SharePoint or in ArcGIS Desktop. For ArcGIS Mapping for SharePoint, we do have an outstanding feature request to enable the joining of SharePoint lists to layers within an ArcGIS Server map service for display within the Map Web Part. This is an enhancement that is currently under consideration for a future release.
Is it possible for ArcGIS to connect to a SP List yet ?
I see the OP was 10 years ago, and last post was 8 years ago.