The selectivity of the copolymerization reaction of propene with carbon monoxide, using cationic palladium complexes modified with various diphosphine ligands as the catalyst precursor, changes toward the formation of low molecular weight compounds in the presence of excess 1,4-benzoquinone. The isomeric composition of the products arising from two propene units and three carbon monoxide molecules, namely of the possible dimethyl 4-oxodimethylheptanedioates, has been analyzed for catalytic systems containing chiral and achiral ligands. The different isomeric and diastereomeric products have been identified and characterized by NMR. The enantiomeric excesses were determined for the products obtained with the chiral ligands, the best enantioselectivity being around 98% ee. In spite of the enantiomer pairs not having been identified with respect to their absolute configuration, this analysis allows us to define the factors responsible for enantioface discrimination during the co-oligomerization. Preferential l-topicity of the two enantiofaces is observed for the products arising from two olefin insertions with the same regioselectivity (isotactic enchainment). A change in the regioselectivity of the insertion process of the olefin always induces a preferential alternation of the enantioface inserted. The catalytic systems investigated show a parallelism relating the feature of regio- and stereoselectivity toward co-oligomerization and copolymerization. The dimethyl dimethyl-4-oxoheptanedioates are regarded as model compounds for the polymerization reaction. The results suggest that the enantioface discrimination during both the regioregular co-oligomerization and copolymerization is related both to the presence of the chiral ligand and to the chiral center of the last inserted olefin unit.