 Furthermore, substitution of 1-methylpyrrole (which can react) with the strongly electron withdrawing tertbutyloxycarbonyl (Boc) group at the 2-position completely inhibits the reaction.The second requirement is for the absence of basic amine groups in the substrate, which would otherwise form an unwanted adduct.This can be illustrated by the lack of a reaction with pyrrole, whereas both 1-methyl and N-benzylpyrrole derivatives are able to react.