Synthesis and Functionalization of N-Heterocycles Using Transition Metal-Free Cross-Dehydrogenative Coupling (CDC) Approaches

Abstract

The creation of carbon–carbon bonds for the construction or the post-functionalization of various N-heterocycles is one of the most active research areas in organic chemistry. Among those approaches, cross-dehydrogenative coupling (CDC) processes in the front line because of its simple, practical applicability in organic synthesis. Historically discovered in the presence of transition metal catalysts, this decade witnessed great progress in the metal-free CDC approaches, thus improving the sustainability of this transformation. This chapter aims at providing an update on selected examples of the metal-free approaches toward the access to various N-heterocycles. The first part deals with the synthesis of N-heterocycles by metal-free CDC approaches in the presence of stoichiometric or catalytic amount of oxidants, whereas the second part is focused on the last stage C–H bond functionalization of N-heterocycles via CDC process.