I spend a good amount of time traveling/working from my phone, an iPhone. By default the iPhone will sync your Exchange personal contact list but not your global address list (GAL).
Here is a quick way to copy the GAL to your persona contact list and therefore have everyone in your contact list.
Go to new email in Outlook
In the contact list, filter by users and select all
Right click and “Add to contacts”
Update or update all to reflect changes