Pyridine Nucleus as a Directing Group for Metal-Based C–H Bond Activation

Abstract

Carbon-hydrogen (C–H) bond activation involves a methodology for the construction of carbon-X (C–X) bonds where X can be carbon (C), oxygen (O), or the nitrogen (N), allowing the formation of C–C, C–O, or C–N bonds. Among them, the construction of the C–C bond within the aromatic moiety has remained a bottleneck because the abundance of C–H bonds in aromatic molecules possesses almost similar bond dissociation energies comparable to the C–C bond allowing leading to the poor reactivity and selectivity. Secondly, C–H bonds possess low polarity and thus confer them inertness. Considering this, directing group strategy came into existence, where the coordination ability of the heteroatoms such as O and N atoms within the ring was utilized for the direction of the reaction. The use of the heteroatom for the regioselective C–H bond activation is quite advantageous that could be explored immensely for their functionalization. In this chapter, we have congregated the information and put forth the evidence of C–H activation leading to the C–C bond formation in pyridine and pyridine-containing entities.