IsoGNA, an isomer of glycerol nucleic acid GNA, is a flexible (acyclic) nucleic acid with bases directly attached to its linear back- bone. IsoGNA exhibits (limited) base-pairing properties which are unique compared to other known flexible nucleic acids. The preparation of isoGNA phosphoramidites and an alternative route for the synthesis of the adenine derivative are described in detail. The synthetic improvements described here enable an easy access to isoGNA and allows for the further exploration of this structural unit in oligonucleotide chemistry thereby spurring investigations of its usefulness and applicability.