I was having this problem. I got the Mac (with Maverick) to sync to the iphone with a bit of a fluke. ICal now only syncs with icloud so I made sure icloud was on, on my phone and then through Calendar Preferences, enabled my Mac to iclound with my apple account and they linked up. Unfortunately, Birthdays that I've have on the cal for a while (all day) now come up twice on my iphone but only once on my Mac. Anyways, at least they are now synced and the frustrations levels with apple have subsided a little. Hope that helps.