Tetrafluoroboric acid as a useful deprotecting reagent in Fmoc-based solid-phase peptide syntheses (Fmoc = fluoren-9-ylmethoxycarbonyl)

Abstract

Tetrafluoroboric acid in trifluoroacetic acid, in the presence of thioanisole, has been found to cleave various protecting groups currently employed in Fmoc-based (Fmoc = fluoren-9-ylmethoxycarbonyl) solid-phase peptide synthesis without significant side reactions; this new deprotecting reagent has been successfully applied to the solid-phase synthesis of human glucagon (a 29 residue peptide) and α-MSH (a 13 residue peptide amide, acetyl-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂).