Im a 10-month Nexus 7 user and i often use the DoubleTwist for Mac to sync my Nexus 7 with iTunes on my Macbook Pro. Followings are the steps:
1. Separately download and install the DoubleTwist for Mac and DoubleTwist for Android onto your iMac and Nexus 7.
2. Connect your Nexus 7 into your iMac...