Mechanochemical Syntheses of N-Containing Heterocycles with TosMIC.

A mechanochemical van Leusen pyrrole synthesis with a base leads to 3,4-disubstitued pyrroles in moderate to excellent yields. The developed protocol is compatible with a range of electron-withdrawing groups and can also be applied to the synthesis of oxazoles. Attempts to mechanochemically convert the resulting pyrroles into porphyrins proved to be difficult.