$t \bar{t}$ production in CMS including the boosted region

We present an ongoing analysis of differential cross section measurements for top-pair (tt) production in proton-proton collisions at a center-of-mass energy of 13 TeV, using events containing two oppositely charged leptons. The data were recorded with the CMS detector at the CERN LHC. We study kinematic distributions of the tt system, the top quark and antiquark and their decay products. For the first time in differential cross section measurements in the dilepton channel, the phase space includes events with highly boosted top quarks (with momenta above several hundred GeV). This phase space is characterised by small angular separations between the leptons and the b jets originating from the top quark decays. This necessitates the inclusion of non-isolated prompt muons and electrons in both the online trigger and the offline analysis. The talk presents the basic event selection and the adaptations made to include the region of boosted top quarks. Initial kinematic distributions are presented alongside estimates of signal and background processes.