If you go to your boss on this matter, your behavior may be regarded as tattling, shirking responsibility, and undercutting a colleague. And further, your boss may ask something like, "If you truly believed that you were right and your mentor was wrong, why didn't you stand up for yourself?"
If you believe that you are not getting useful advice from your mentor, the first place to look is at yourself, particularly in terms of your ability to act assertively in support of your ideas. In fact, when you demonstrate the self-assurance needed in this type of situation, perhaps your mentor and management will see that you are ready to work on your own.
However, if you still want to go to management, your objective should not be to criticize or blame your mentor for anything. Rather, your objective should be to demonstrate to management that you are ready for more autonomy. Be sure to bring in specific data from your work and educational experiences to show that this is the case.
One less obvious point that you hopefully learned from your mentor is to listen extra carefully when others disagree with you. This lesson is going to help you become a better employee, manager, and future mentor.
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