The H-phosphonate approach to the synthesis of phosphopeptides on solid phase

Ammonium tert-butyl H-phosphonate was used for the phosphorylation of Tyr- and Ser-containing peptides synthesized by an Fmoc strategy. This reaction, leading to a monoprotected peptide phosphate, was found to be highly effic ient and generally applicable. Moreover, the method employed avoids undesir ed side reactions during chain elongation (pyrophosphate formation and beta -elimination catalyzed by piperidine).