An extensive review on transition metal catalyzed indole C H activation: Catalyst selection and mechanistic insights

• Transition metal-catalyzed C H activation reactions of indole molecule. • Review focuses on the palladium, rhodium, iridium, ruthenium, and manganese catalyzed C H activation reactions. • Incorporating exhaustive synthetic strategies and mechanisms. The present review article explores the expansive synthetic methodologies facilitated by C H activation of indoles using transition metal catalysts. The strategic utilization of catalysts such as palladium, rhodium, iridium, ruthenium, and manganese has revolutionized organic synthesis by enabling selective alkynylation, acylation, and annulation reactions. These transformations are pivotal in pharmaceuticals, particularly in the synthesis of antihistamines and potential antiviral drugs against SARS-CoV-2. Additionally, these catalysts play a crucial role in perfumery and other chemical industries, enhancing the efficiency and precision of compound synthesis. The choice of transition metal catalysts is informed by their affordability and compatibility with both traditional analytical methods and innovative techniques like microwave synthesis and LED irradiation. Furthermore, this review underscores the interdisciplinary impact of transition metal-catalyzed C H activation on indoles, highlighting its significance in advancing both fundamental organic chemistry and applied sciences essential for modern technological advancements and drug discovery efforts.