for the synthesis of a thyminyl PNA dimer and then used to synthesize two different chiral PNAs. In this way two advantages were obtained: a lower degree of racemization in the coupling step during the solid-phasesynthesis and the possibility of using the same submonomer for every different nucleobase. All the D-lysine-based chiral PNAs were obtained in good yields and, as compared with PNAs synthesized