If you were to tell us a bit more about what you are looking for (what should your integration handle etc) it is easier to point you in the correct direction. Since you have not stated anything regarding this I am just gonna through some links at you and hope that some of these help you out:
Connecting to SharePoint
Import/Connect to Sharepoint using the OData connector
Can the OData Connector be used to connect to MS Office 365 Sharepoint Online?
Get to know the SharePoint 2013 REST service
Use OData query operations in SharePoint REST requests
We recently integrated a Sharepoint app running in a private cloud with Boomi. In this particular use case, Sharepoint was pretty limited in accessing date on other platforms (SQL was not an option). REST API's was an option so we create one on the Boomi platform and it works as a breeze. In our case, we have no CORS policies applied (wasn't necessary) and I was happy because that isn't easy to setup...at least in our case.
Old thread but trying anyway: Sjaak Overgaauw did you successfully create a call to a sharepoint instance, creating a folder and/or document? It appears it is creating docs that often is an issue?
Integrating thru documents and folders wasn't part of the scope at the time. This was a Sharepoint app calling a Boomi REST API to post data. Btw: I haven't worked on Sharepoint integrations lately. I can't comment if things have improved on the Sharepoint side since then.
Retrieving data ...