Modern strategies for C–H functionalization of heteroarenes with alternative coupling partners

Heteroarenes containing oxygen, nitrogen, and/or sulfur are important in numerous aspects of chemistry and everyday life. C–H functionalization of heteroarenes represents the fastest and most atom-economical approach for the synthesis of complex molecules. This strategy avoids the requirement of de novo synthesis and is beneficial for the late-stage modification of structurally complex molecules. Although early protocols for C–H functionalization using organic halides (I, Br, and Cl) as coupling partners remain in active use today, a range of modern strategies allows the cleavage of less reactive C–Het (F, O, S, N, and P) and C–C bonds to form essential links to the feedstock chemicals, highlighting their renewable and sustainable features. This review focuses on modern strategies for the C–H functionalization of heteroarenes with these alternative coupling partners. Most of the transformations can be achieved through catalytic processes. Some non-catalytic strategies involving new reagents and techniques are also introduced.