  The decay modes of the type $B \to \pi \, D $ are dynamically different. For
the case $\bar{B_{d}^0} \to \pi^- D^{+} $ there is a substantial factorized
contribution which dominates. In contrast, the decay mode $\bar{B_{d}^0} \to
\pi^0 D^{0} $ has a small factorized contribution, being proportional to a very
small Wilson coefficient combination. In this paper we calculate the relevant
Wilson coefficients at one loop level in the heavy quark limits, both for the
$b$-quark and the $c$-quark. We also emphasize that for the decay mode
$\bar{B_{d}^0} \to \pi^0 D^{0}$ there is a sizeable non-factorizable
contribution due long distance interactions, which dominate the amplitude. We
estimate the branching ratio for this decay mode within our framework, which
uses the heavy quark limits, both for the $b$- and the $c$-quarks. In addition,
we treat energetic light ($u,d,s$) quarks within a variant of Large Energy
Effective Theory and combine this with a new extension of chiral quark models.
For reasonable values of the model dependent parameters of our model can
account for at least 3/4 of the amplitude needed to explain the experimental
branching ratio $\simeq 2.6 \times 10^{-4}$.
