Sync apps from computer to iPhone using iTunes I am unable to transfer apps from my computer to iPhone 5 running 6.0.1. Whenever I click on the Install button the button changes to Will Install. 

Similarly, as soon as I click on the Sync button. synchronization terminates without any error at the step Determining apps to sync.

Any ideas on how I can fix this?
Sounds like you might need to do a factory reset on the phone (AFTER DOING A BACKUP!).

Best to backup to your computer instead of to iCloud, since there are some things that are not backed up to iCloud.

Alternatively, just used the "purchased -> not on this phone" feature in the app store on the device. That will also let you install any app.