LNA stereoisomers: xylo-LNA (β-D-xylo configured locked nucleic acid) and α-L-LNA (α-L-ribo configured locked nucleic acid)

Synthesis of xylo-LNA containing one 2′-O,4′-C-methylene-β-D-xylofuranosyl thymine nucleotide monomer and α-L-LNAs containing one or four 2′-O,4′-C-methylene-α-L-ribofuranosyl thymine nucleotide monomer(s) has been accomplished using phosphoramidite chemistry with pyridine hydrochloride as activator; oligothymidylate α-L-LNA displays strongly enhanced affinity towards complementary RNA.