SCHEME 1.
General procedures for the synthesis of (S)-GNA (top) and (R)-GNA (middle) phosphoramidites starting from enantiopure glycidol. Various bases and base analogs (B) can be used to functionalize GNA (bottom). Detailed protocols for syntheses have been reported (Zhang et al. 2005, 2006; Schlegel and Meggers 2009; Schlegel et al. 2017, 2021).