Résumé
Constrained nucleic acids (α,β‐D‐CNAs) have an ethylene bridge that locks the α and β backbone torsion angles of DNA in the canonical (gauche(−),trans) conformation, as in B‐form DNA (see picture), or in the noncanonical (gauche(+),trans) conformation. Canonical α,β‐D‐CNAs enhance the duplex‐forming ability of oligonucleotides with complementary DNA, while noncanonical α,β‐D‐CNAs stabilize distorted B‐DNA structures.