Anchoring of Fmoc amino acid to 4-alkoxybenzyl alcohol resin using a new esterification reagent

Abstract

Esterification of Fmoc (fluoren-9-ylmethyloxycarbonyl) amino acid or amino acid derivative to 4-alkoxybenzylalcohol resin was achieved in generally good yield using a new esterification reagent, CIP [2-chloro-1,3-dimethylimidazolidinium hexafluorophosphate] or BOI [2-(benzotriazol-1-yl) oxy-1,3-dimethylimidazolidinium hexafluorophosphate]. The reaction was rapider with the same or lower racemization level than the anchoring reaction using the conventional esterification reagents.