std::unique_ptr and a template

I have a scenario where I use CRTP. pseudo code below;

template <typename T>
class Base {} 

class Derived1 : Base < Derived1 >  {}

class Derived2 : Base < Derived2 > {} 

everything works fine EXCEPT when I introduce unique_ptr in to the loop. I want to have a unique_ptr to Base and elsewhere in the code use this to take ownership of either a Derived1 or Derived2 pointer.

// declaration - this is the problem - wont compile.
std::unique_ptr<Base> base_unique_ptr;

// cpp , elsewhere.

base_unique_ptr.reset(new Derived1());

or

base_unique_ptr.reset(new Derived2());

am I in trouble? I don't want to change the existing codes use of unique_ptr.

unique_ptr<