Importance and synthesis of benzannulated medium-sized and macrocyclic rings (BMRs)

Cyclic molecular frameworks, especially the benzannulated medium-sized and macrocyclic ring (BMR) systems, constitute an integral component of a large number of biologically significant natural or synthetic molecules. Many of these BMR compounds are either approved as drugs or have reached the late developmental stages in clinical trials. Such cyclic systems have been shown to possess great potential, especially in the discovery of new anticancer leads. Efforts from synthetic chemists have led to the development of elegant new strategies for the construction of BMR scaffolds of medicinal importance. This review intends to highlight the importance of benzannulated medium-sized and macrocyclic rings (BMRs) and the strategies developed over the years for their synthesis.