In the paper 'On the complex projective spaces' of HirzbruchOn the complex projective spaces, Hirzebruch and Kodaira, they prove thatthe following:
If $X$ is compact Kähler manifold diffeomorphic to $\mathbb{CP}^n$, then $X$ is biholomorphic to $\mathbb{CP}^n$ in caseif $n$ is odd or $n$ is even but $c_1 \neq -(n+1)g$.
Here, $c_1$ is the first Chern class of $X$, and $g$ is a generator of $H^2(X,\mathbb{Z})$ with the same sign ofas the Kähler class.
My question is: Has the case $X$ is diffeomorphic but not biholomorphic to $\mathbb{CP}^n$, with $n$ even and $c_1=-(n+1)g$ been ruled out in the following years? Or do we have some constructions of manifolds of this type?