Two-loop master integrals for a planar topology contributing to $pp\to t\bar{t}j$

We report on recent progress for the QCD corrections to top quark pair plus jet production. In particular, we discuss a recent computation for the two-loop master integrals associated to a two-loop five-point pentagon-box integral configuration with one internal massive propagator, that contributes to top quark pair production in association with a jet in the QCD planar limit.