Synthesis of naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines via Rh(iii)-catalyzed C–H functionalization of 2-arylimidazo[1,2-a]pyridines with cyclic 2-diazo-1,3-diketones featuring with a ring opening and reannulation

Abstract

An unprecedented synthesis of functionalized naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines via rhodium-catalyzed cascade reactions of 2-arylimidazo[1,2-a]pyridine-3-carbaldehydes with cyclic α-diazo-1,3-diketones is presented.

Transition‐Metal‐Catalyzed C−H Bond Functionalization of Arenes/Heteroarenes via Tandem C−H Activation and Subsequent Carbene Migratory Insertion Strategy

“…Li and Fan group recently reported the synthesis of functionalized naphtho[1',2':4,5]imidazo[1,2-a]pyridines via a Rh(III)-catalyzed cascade reaction of 2-arylimidazo[1,2-a] pyridine-3-carbaldehydes with cyclic α-diazo-1,3-diketones (Scheme 22c). [62] It happens to be the first of such reports aiming towards the formation of carbocyclic scaffolds generated via CÀ H bond activation/carbene insertion and a [5 + 1]-annulation by using Indole functionalization resulting from carbene insertion/ annulation gives rise to substituted fused-carbocycles. Usually the C(2)À H of indoles gets activated owing to the close proximity of the directing group.…”

Simple inorganic base promoted polycyclic construction using mucohalic acid as a C3 synthon: synthesis and AIE probe application of benzo[4,5]imidazo[1,2-a]pyridines

“…It is well known that some benzo[4,5]imidazo[1,2- a ]pyridine compounds often have good fluorescence properties. 2,18,38 Herein, the C 1 position of the benzo[4,5]imidazo[1,2- a ]pyridine molecules is occupied by an N-heterocyclic ring, and the fluorescence properties of this framework are worth exploring. Therefore, we chose 4a as the representative compound to study the photophysical properties.…”

“…Among them, N-heterocycles as typical molecular frameworks of synthetic drugs, natural products, agrochemicals and functional materials, are widely used in organic synthetic chemistry. 1 For example, benzo[4,5]imidazo-[1,2- a ]pyridines are not only a class of significant fluorescent material molecules, 2 but also have potential medicinal properties, such as antidiabetic, 3 anti-cancer, 4–6 anti-malarial, 7,8 antifungal, 9 antischistosomal, 10,11 etc . It is worth noting that benzo[4,5]imidazo[1,2- a ]-pyridines containing a C 1 –N bond have excellent biological activities (Fig.…”

Ruthenium-Catalyzed C(sp2)–H Bond Bisallylation with Imidazopyridines as Directing Groups

“…Until now, great progress has been made in C3-functionalization of imidazopyridines, including formation of C–C, C–S, C–Se, and C–N bonds (Scheme a). On the contrary, imidazopyridine-directed C–H functionalization is less investigated (Scheme b) . Specially, the Hajra group has achieved C–H amidation of imidazoheterocycles with dioxazolones .…”