If I'm looking at things properly, the newest version of iTunes requires a minimum of 10.6.8. If you've been doing your software updates on your Mac you should be good to go.
Not so much 10.6.8, per se - but you need iTunes 11.4 or later for syncing.
From iPhone 6 System Requirements:
Syncing with iTunes on a Mac or PC requires:
Mac: OS X v10.6.8 or later
PC: Windows 8; Windows 7; Windows Vista; or Windows XP Home or Professional with Service Pack 3 or later
iTunes 11.4 or later (free download from www.apple.com/itunes/download)