Fmoc‐Protected Altritol Phosphoramidite Building Blocks and Their Application in the Synthesis of Altritol Nucleic Acids (ANAs)

Fmoc‐protected altritol nucleoside phosphoramidite building blocks with adenine, guanine, thymine, uracil, cytosine and 5‐methylcytosine as bases have been synthesized. These building blocks were used for the synthesis of altritol nucleic acid (ANA) and chimeric ANA‐RNA oligonucleotides. Whilst the yields of oligonucleotides were lower than those obtained with 3′‐ O ‐benzoyl‐protected altritol building blocks, the excellent compatibility with Pac‐RNA chemistry for the synthesis of chimeric oligonucleotides makes Fmoc a valuable protecting group for the secondary alcohol functions of the sugar moieties of nucleosides for oligonucleotide synthesis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)