Protecting groups in the form of N-alkyl or N-aryl substituents hold a key position in heterocyclic chemistry in that selected groups on nitrogen frequently make possible the synthesis of ring compounds, which are otherwise inaccessible. Bulky N-protecting groups often provide control over the reaction pathway and heterocycle formation through Mannich condensations1 and Gaertner cyclizations, 2 to cite two examples. The versatility of this ...
