Towards fluorous-phase synthesis of nucleoside beta-peptides

We have recently shown that peptides derived from nucleoside beta-amino acids adopt an unusual 8-helical conformation in solution(1). These beta-peptide homooligomers were constructed using Fmoc solid-phase peptide synthesis protocols (SPPS); however, we found these procedures to be somewhat limiting in terms of scale and lacking a quantitative method of monitoring reactions. Preliminary investigations into the use of fluorous dendrons as an alternative to SPPS have been conducted and show that coupling reactions with modified nucleoside (1) and fluorous dendrimer (2) are possible in the presence of a glycine linker. Significantly, success of the coupling reactions could be monitored by NMR without loss of materials or termination of the synthetic sequence and this promises much for the future of both oligonucleotide and polypeptide synthesis.