FIGURE 1.

A, exemplary transformation of brevianamide F (E1) to tryprostatin B (E3). B, regiochemistry of the nucleophilic attack on the prenyl moiety. For regular prenylation, bond formation occurs between C2 and the carbon adjacent to the pyrophosphate group. An attack of C2 on the tertiary carbon of DMAPP leads to the reversely prenylated product. C, illustration of the SMIRKS-like notation derived from A (generated by SMARTSviewer) (22). GA, general prenyl moiety acceptor; GD, general prenyl moiety donor; GB, general base; GP, general prenylation product; PP, pyrophosphate; PGB, protonated general base. D (left), a reactive epitope indicated around the reactive atom ([cH1:1]) with the atomic properties given in SMARTS nomenclature (brackets). D (right), reactive epitope as generated by SMARTSviewer.