Ruthenium(ii)-catalyzed regioselective direct C4- and C5-diamidation of indoles and mechanistic studies

Abstract

A ruthenium(II)-catalyzed regioselective direct diamidation of 3-carbonylindoles at the C4- and C5- position using various dioxazolones is described. This novel protocol allows for the effective installation of two amide groups...

Transition metal-catalyzed regioselective functionalization of carbazoles and indolines with maleimides

“…Recently, our group developed novel methodologies for the synthesis of heterocycles 27 and the introduction of amide groups 28 on the indole ring via C–H activation. As part of our ongoing efforts to introduce heterocycles onto aromatic rings, we herein report the ruthenium-catalyzed regioselective C–H functionalization of carbazoles with maleimides for the introduction of succinimides at the C-1 position (Scheme 1B).…”

Theoretical Study on Ir-Catalyzed α-Amidation of 2-Acylimidazoles: Mechanism and Insertion Selectivity

“…α-Amino carbonyls, as a class of N-containing compounds, are not only ubiquitous structural motifs in natural products and pharmaceuticals but also high-value synthons of N-heterocycles and chiral 1,2-amino alcohols. − However, the traditional synthesis of α-amino carbonyls often suffers from the requirement of prefunctionalized starting materials or the scarce availability of N-electrophiles. , C–H amidation realized by transition-metal-catalyzed nitrene transfer has several advantages including eliminating the requirement of prefunctionalized starting materials and the formation of undesired byproducts. Transition metals, such as Ir, − Rh, − Co, , Ru, , Cu, , and Pd, are usually used as catalysts for these nitrene transfer reactions. This advanced synthetic strategy has been gradually employed to the construction of α-amino carbonyls in recent years but still faces the challenge of limiting substrate scope or low functional group compatibility. − Noteworthily, Chatani’s group recently reported Ir-catalyzed selective α-amidation to synthesize α-amino carbonyls with a broad range of carbonyl substrates (2-acylimidazoles) .…”

“…20,21 C−H amidation realized by transition-metal-catalyzed nitrene transfer has several advantages including eliminating the requirement of prefunctionalized starting materials and the formation of undesired byproducts. Transition metals, such as Ir, 22−25 Rh, 26−28 Co, 29,30 Ru, 31,32 Cu, 33,34 and Pd, 35 are usually used as catalysts for these nitrene transfer reactions. This advanced synthetic strategy has been gradually employed to the construction of α-amino carbonyls in recent years but still faces the challenge of limiting substrate scope or low functional group compatibility.…”

Palladium‐Catalyzed Regioselective C4 Functionalization of Indoles with Quinones

“…Recently, we established a protocol for the Ru‐catalyzed C−H activation of 3‐formylindoles with dioxazolones to introduce the amide functionality onto the indole ring [24] . As an ongoing study, we hypothesized that a transition metal‐catalyzed C−H activation process could be used to introduce a diverse range of quinones at the C4 position of indoles.…”

“…Recently, we established a protocol for the Rucatalyzed CÀ H activation of 3-formylindoles with dioxazolones to introduce the amide functionality onto the indole ring. [24] As an ongoing study, we hypothesized that a transition metal-catalyzed CÀ H activation process could be used to introduce a diverse range of quinones at the C4 position of indoles. Thus, herein we report a Pd-catalyzed coupling reaction of 3-carbonylindoles with 1,4-benzoquinones, 1,4-napthoquinones, or 1,4-anthracenediones to regioselectively introduce biologically interesting quinonyl moieties at the C4 position of indoles via single and double CÀ H activation processes (Scheme 1c).…”