Using a brushless DC motor for generator
You can't make something out of nothing.

Yes, you can "reclaim" energy from the front wheels while driving the back wheels.  However, the energy that you remove through the front wheels has to come from somewhere, and that somewhere is the back wheels.

The driving energy will have to increase to compensate for the extra load of the power generating wheels.

Electric and hybrid cars already use a similar system to reclaim wasted energy used during braking (which would usually be dissipated as heat), and it's called Regenerative Braking