Fig. 3. Reaction time dependence and reaction pathways of the phosphorylation.

a Yields depending on the reaction time starting from A (100 mM), H₃PO₃ (3.0 eq.) and urea (1.0 eq.). Depicted are mean values, error bars refer to ± s.d and were obtained by double determination via CE (for yield calculation see supplementary information). b Proposed reaction pathways for phosphorylated compounds. Constitution of potential isomers has not been determined. Labels refer to the entirety of all observed isomers (black = m/z value found; red = m/z value not detected; oxidation: ox.). For simplification and since we did not detect the A-p^V-p^III-p^III/ p^III-A-p^V-p^III/p^III-A(p^V)-p^III intermediate, we did not show the inverse reaction sequence (first condensation, second oxidation) for the reaction of A-p^V-p^III/p^III-A-p^V to A-p^V-p^V-p^III/p^III-A-p^V-p^V/p^III-A(p^V)-p^V.