Synthesis and Structure of Dinucleotides with S‐Type Sugar Puckering and Noncanonical ϵ and ζ Torsion Angle Combination (ν2,ϵ,ζ‐D‐CNA)

Abstract

AbstractThe synthesis of the diastereoisomers of ν2,ϵ,ζ‐D‐CNA dinucleotide building units of nucleic acids and their (2′,5′)‐ν2,ϵ′,ζ′‐D‐CNA analogues, in which the ϵ and ζ torsional angles are stereocontrolled by a dioxaphosphorinane ring structure (D‐CNA family) is described from a common 3‐deoxy‐3‐(hydroxymethyl)‐D‐allofuranose intermediate. NMR spectroscopic and circular dichroism structure analysis of ν2,ϵ,ζ‐D‐CNA shows that the sugar puckering is fixed in the C‐2′‐endo conformation and that these D‐CNA structuralelements allow stabilization of the ϵ/ζ torsion angle combinations, which are significantly different from the typical combinations observed in canonical A‐ or B‐form duplexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)