Recent advances in intramolecular C–O/C–N/C–S bond formation via C–H functionalization

This review focuses on the intramolecular cyclization of molecules through C–O, C–N and C–S bonds forming C–H functionalizations with an emphasis on the literature after 2000. Intramolecular C–H functionalization reactions attract much interest because of the ease of reaction due to the proximity of reacting centers and favorable entropy over intermolecular reactions. Less by-product formation, high atom economy, ease of purification, and avoidance of prefunctionalization of substrates are the additional advantages. Hence, a number of research articles have been published in this field, but no review is available so far. This review includes the synthesis of various heterocycles involving C–O, C–N and C–S bond creation. This is the first review on the current topic which will motivate the readers to work in this area further.