Just sync normally and don't restore and you won't be forced to update.
If you're asking how to get your music from your iPhone onto your Macbook, there's no easy way to do it. I recently had to do this because I bought a new Macbook as well and I used iExplorer to pull my music from the device, then added that folder to iTunes. It got all my music into iTunes but some of the songs had random names like "AHET" or "MNH4" etc, took about an hour to rename the ones that didn't come out right.
Other than that, when you plug in your phone. Log onto iTunes with the Apple id you used with your iPhone, and in File click Transfer Purchases then just sync normally and everything should be good.