Let $\mathfrak{g}$ be a real Lie algebra of dimension $2n+1$ and let $\mathfrak h \subset \mathfrak g \otimes \mathbb C$ be a subalgebra of complex dimension $n+1$ satisfying $\mathfrak h + \overline{\mathfrak h} = \mathfrak g \otimes \mathbb C.$ When does there exist a subalgebra $\mathfrak h' \subset \mathfrak h$ of dimension $n$ such that $\mathfrak h' \cap \overline{\mathfrak h'} = \{0\}$?
I also would not mind requiring that $\mathfrak{g}$ is the Lie algebra of a compact Lie group.