Synthesis of spiro[benzo[d][1,3]oxazine-4,4′isoquinoline]s through a unique [4+1+1] annulation of N-aryl amidines with diazo homophthalimides and O 2 is presented. This unprecedented spirocyclization reaction features readily obtainable substrates, structurally and pharmaceutically attractive products, a cost-free and clean oxygen source, sustainable reaction medium, tolerance of a broad spectrum of functional groups, and an interesting reaction mechanism based on sequential C(sp 2 )−H/ C(sp 3 )−H bond cleavage and oxygen insertion.

In vivo H2 O 2 visualization is crucial for disease diagnosis. Catalytic reactionbased probes show potential in H 2 O 2 detection, yet their in vivo application remains challenging because catalysts always require a specific pH to function and cellular glutathione (GSH) may suppress signaling by depletion of hydroxyl radicals and oxidized substrates. Here, a microenvironment-tailored catalytic nanoprobe (MTCN) comprising Fe 2+ , citric acid (CA), 2,2′-azino-bis(3ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and downconversion nanoparticles in the liposomal cavity as well as a reference dye in the lipid membrane is reported, which utilizes the selective permeability of the liposomal membrane to offer a favorable pH for Fe 2+ catalyst with the aid of CA and to avoid GSH-triggered signal loss by preventing entry of GSH into the cavity. The MTCN displays a large NIR-II fluorescence (FL) ratio between 1550 and 1080 nm (FL 1550Em,808Ex /FL 1080Em,980Ex ), but a small photoacoustic (PA) ratio between 808 and 1048 nm (PA 808 /PA 1048 ). Upon exposure of MTCN to H 2 O 2 , catalytic conversion of ABTS into its oxidized form ABTS• + with 808 nm absorption causes a noticeable increment in PA 808 /PA 1048 accompanied by an apparent decrement in FL 1550Em,808Ex /FL 1080Em,980Ex , enabling bimodal ratiometric imaging of H 2 O 2 in the tumor and lymphatic metastasis.

In this paper, an efficient synthesis of functionalized 1,3-benzodiazepines through an unprecedented [5 + 2] annulation of N-aryl amidines with propargylic esters is presented. The reactions proceed through Rh­(III)-catalyzed C­(sp2)−H alkenylation followed by annulation and deacetoxylation along with cascade C−H/N−H/C−O bond cleavage and C−C/C−N bond formation. Furthermore, the cytotoxicity of selected products against several human cancer cell lines was tested, which demonstrated their good potential for pharmaceutical applications.

In this paper, an efficient synthesis of 3-spirooxindole 3H-indoles through the coupling and spirocyclization of N-aryl amidines with diazo oxindoles is presented. Mechanistically, the formation of the title products involves...

A one-pot simultaneous synthesis of 2,2,2-trifluoroethylphenanthridines and benzochromenones featuring the utilization of the byproduct of Togni's reagent is presented.

An efficient synthesis of α-amidoketone derivatives through the cascade reactions of carboxylic acids with vinyl azides is presented. Compared with literature protocols, notable features of this new method include catalyst-free conditions, broad substrate scope, good tolerance of a wide range of functional groups, and high efficiency. In addition, the synthetic potential of this method as a tool for late-stage modification was convincingly manifested by its application in the structural elaborations of a number of carboxylic acid drug molecules.

Presented herein is a novel and efficient α-C(sp 3 )− H alkenylation of cyclic amines with maleimides. Mechanistically, this C(sp 3 )−H/C(sp 2 )−H cross dehydrogenative coupling (CDC) reaction involves a cascade procedure including oxidative α-amino radical formation from the cyclic amine substrate and nucleophilic addition of the in situ formed α-amino radical onto the electrondeficient carbon−carbon double bond of maleimide followed by oxidation and β-elimination. Notably, this direct α-functionalization provides an effective alternative to the conventional ionic reaction mode, in which an imine or iminium intermediate is formed to react with electron-rich coupling partners other than electron-deficient ones. In general, this method features readily available and structurally diverse substrates, a green and economical catalyst, a unique reaction pathway, mild reaction conditions, high efficiency, and excellent atom economy. This new reaction enriches the application of Fe(III)-catalyzed C(sp 3 )−H activation and functionalization.

Presented herein is a condition‐controlled divergent synthesis of imidazoindolone spiro‐isoquinolinones (IISIQs) via the cascade reactions of N‐alkoxycarboxamide indoles with diazo homophthalimides. When the reaction is carried out under air and in the absence of an acid additive, IISIQ tethered with a N‐alkoxy moiety (IISIQ‐OR) is formed through Rh(III)‐catalyzed C−H/N−H metalation, carbene formation/ migratory insertion followed by reductive elimination, in which air acts as an oxidant to regenerate the Rh(III) catalyst. When the reaction is run under argon and in the presence of MesCO2H, on the other hand, IISIQ−H is formed through rhodacycle intermediate formation, carbene insertion followed by acid‐assisted intramolecular substitution/annulation and N−O bond cleavge. In general, this method provides a divergent approach toward spiroheterocyclic scaffolds and features accessible substrates, functional group compatibility and air as an external oxidant. Moreover, the value of this developed protocol is further showcased by gram‐scale synthesis and structural transformation of products.