Convenient synthesis and cyclization of dimeric abasic PNA

The synthesis of an abasic PNA-based dimer block has been achieved. An alkyl chain stapling the two base sites conformationally restricts the PNA backbone, and serves as an example of preorganization by direct base site linkage. Other possible examples of this strategy, such as enforced stacking of adjacent intrastrand bases to give base pair step analogs, are put forward.