Transition metal-catalyzed C–H functionalizations of indoles

Abstract

Over the last two decades, transition-metal catalyzed C-H functionalization of indoles has emerged as an area of extensive research and tremendous progress has been made in this regard. Early developments...

Transient Directing Group Strategy as a Unified Method for Site Selective Direct C4–H Halogenation of Indoles

“…Indole is a kind of important biologically active naturally occurring alkaloid, and it also constitutes representative core architecture for extensive pharmaceutical molecules . Consequently, direct functionalization on the indole ring became one of the most straightforward protocol for rapid access to structure and property diversified indole derivatives . It is well-known that both C2- and C3-positions of indole exert much higher reactivity than the other positions; thus, it remains a long-standing challenging topic to install functional groups on the benzenoid moiety of the indole skeleton .…”

Ir-Catalyzed Enantioselective Formal C–H Conjugate Addition of Pyrrole and Indoles to α,β-Unsaturated Carbonyl Compounds

“…6 Transition-metal-catalyzed C−H activation is a fascinating and complementary strategy for the direct functionalization of indoles. 7 We achieved branch selectivity in the Ir-catalyzed C− H alkylation of indole with styrene by the combination of a directing group (DG) on the nitrogen atom and diphosphine ligand. 8 While we further examined an enantioselective reaction, the ee was moderate (43% ee).…”

Cobalt catalyzed decarbonylative ipso-C-C bond functionalization: Synthesis of Indole C-3 functionalized acyloins using 1,2-diketone

“…Whereas, a mixture of both these fluorinated solvents resulted in only a slight improvement in the yield (Table S1, entry 4). Next, we varied the silver-based additives such as AgSbF6 and AgNTf2 instead of AgBF4, but no improvement in yield was observed (Table S1, entry [5][6]. The amount of copper acetate and its variation from Cu(OAc)2 to AgOAc was also not helpful for obtaining a better result (Table S1, entry 7-8).…”

“…4 In this context, the sp 2 C-H bond functionalisation of indole at the C3 position has been accomplished through directed (Figure 1a), as well as non-directed pathways. 5 Among these two types of metalation, the directed sp 2 C-H functionalisation has been explored by installing a directing group at the C2 position. Benjamin Pelcman et al have previously reported the palladium and platinum-catalysed acetoxylation of indole at C3 position using C2 ester as coordinating group.…”