ortho-Halobenzyl Halides as Precursors for the Synthesis of Five- to Nine-Membered Ring Structures Employing Transition Metals as Catalysts

This review highlights the multifaceted usefulness of o-halobenzyl halides as pivotal substrates for the construction of five- to nine-membered cyclic structures with the aid of transition metals as catalysts. These privileged entities engage dual active sites, enabling the combination of both intermolecular benzylation and intramolecular arylation strategies that directs the formation of a diverse repository of cyclic structures. The introduction of transition-metal catalysis in cross-coupling transformations sparked a revolution in forging aryl–heteroatom bonds, culminating in the evolution of more potent methodologies for the synthesis of a wide spectrum of valuable compounds. Furthermore, the associated pharmaceutical and biological attributes of these cyclic structures augment their significance in medicinal chemistry research. This review aims to showcase the importance of this synthetic methodology and its far-reaching applications in synthesis. 1 Introduction 2 Synthesis of Five-Membered Rings 3 Synthesis of Six-Membered Rings 4 Synthesis of Seven-Membered Rings 5 Synthesis of Eight- and Nine-Membered Rings 6 Conclusion