Chemodivergent Synthesis of Indeno[1,2-b]indoles and Isoindolo[2,1-a]indoles via Mn(III)-Mediated or Electrochemical Intramolecular Radical Cross-Dehydrogenative Coupling

Orthogonal Synthesis of Cationic Azatriphenylene Derivatives for Aggregation-Induced Emission (AIE) and Aggregation-Caused Quenching (ACQ) Property Switching

Herein, we report a divergent synthesis of cationic azatriphenylene derivatives using orthogonal control of thermal and electro-oxidative pyridination, which transforms the single precursor into controlled products with perfect selectivity. Simultaneously, two switchable reactions afford the corresponding pyridinium salts with different optical properties such as aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) effects.

Rhodaelectro-Catalyzed Synthesis of Pyrano[3,4-b]indol-1(9H)-ones via the Double Dehydrogenative Heck Reaction between Indole-2-carboxylic Acids and Alkenes

A rhodaelectro-catalyzed double dehydrogenative Heck reaction of indole-2-carboxylic acids with alkenes has been developed for the synthesis of pyrano[3,4-b]indol-1(9H)-ones. The weakly coordinating carboxyl group is utilized twice as a directing group to activate the C-H bonds throughout the reaction. This reaction precedes an acceptorless dehydrogenation under exogenous oxidant-free conditions in an undivided cell with a constant current.

Manganese-Catalyzed Cycloalkene Ring Expansion Synthesis of Azaheterocycles

Herein, a Mn catalytic protocol has been developed for the cycloalkene ring expansion synthesis of azaheterocycles, allowing broad-substrate-scope access to pyridine and isoquinoline derivatives. The initial monoaddition of an azidyl radical to alkene and further as-generated C-radical addition to O2, followed by intramolecular rearrangement and aromatization, showcase a distinct Mn-catalyzed radical reactivity mode. The reaction features a short reaction time and a broad substrate scope, with applications demonstrated in complex structure elaboration and gram-scale vismodegib synthesis.

A Lewis Acid-Catalyzed Cascade Synthesis of Fused N-Heterocycles from 2-Alkynylanilines and 2-Formylbenzonitriles: Unveiling Iminoisoindoloindolone and Its Derivatives

We herein reveal a streamlined synthesis of structurally fused 6-iminoisoindoloindolones via a meticulously orchestrated cascade reaction. This process seamlessly intertwines 2-alkynylaniline and 2-formylbenzonitrile under the catalytic influence of TMSOTf, giving rise to these compounds in remarkable yields that stand as a testament to the efficiency of our approach. Moreover, the versatility of this synthetic strategy extends far beyond mere synthesis, offering a gateway to the creation of both isoindoloindolone and unprecedented diphenylbenzopyrrolizinoisoquinolinone derivatives, thereby opening new horizons in the realm of chemical innovation. Furthermore, the strategic elegance of this synthetic methodology is underscored by its potential for scale-up production and applicability across diverse chemical contexts.

Cascade Electrochemical Aerobic Oxygenation of 2-Substituted Indoles and Electrochemical [5 + 3] Annulation with Amidines: Access to Eight-Membered Benzo[1,3,5]triazocin-6(5H)-ones

The cascade electrochemical C3-selective aerobic oxygenation of 2-substituted indoles and electrochemical [5 + 3] annulation with amidines through an undivided cell galvanostatic method employing molecular oxygen and "electricity" as green oxidants was developed. This protocol provides an efficient and direct approach to eight-membered benzo[1,3,5]triazocin-6(5H)-ones. Mechanistic studies suggested that two subsequent electrochemical processes both proceeded through radical pathways.

Iodine-Mediated C2,3-H Aminoheteroarylation of Indoles

A metal-free one-pot oxidative cross-dehydrogenation coupling reaction for the formation of C-N/C-C bonds at the C2,3-positions of indoles with azoles and quinoxalinones has been developed. The proposed method has several notable features, including metal-free catalysis, the use of N-H free indoles as substrates, ease of operation, mild reaction conditions, and compatibility with a wide range of substrates.

Rhodaelectro-Catalyzed Decarboxylative Cross-Dehydrogenative Coupling of Indole-3-carboxylic Acids and Olefins via Weakly Coordinating Carboxyl Groups

A rhodaelectro-catalyzed C2-H selectively decarboxylative alkenylation of 3-carboxy-1H-indoles employing electricity as the traceless terminal oxidant has been accomplished. The weakly coordinating carboxyl group serves as the traceless directing groups. External oxidant-free in an undivided cell with constant current in aqueous solution ensures the decarboxylative C-H alkenylation to be viable and sustainable.

Mn(OAc)3-Promoted Sulfonation-ipso-Cyclization Cascade via the SO3- Radical: The Synthesis of Spirocyclic Sulfonates

A radical sulfonation-ipso-cyclization cascade promoted by Mn(OAc)3·2H2O using functionalized alkynes or alkenes and potassium metabisulfite (K2S2O5) is reported. A total of 30 spirocyclic sulfonates were synthesized under mild conditions. We also demonstrate a modular synthesis approach in multiple steps for the preparation of various azaspiro[4,5]-trienone-based sulfonamides and sulfonate esters.

Chemodivergent Photocatalyzed Heterocyclization of Hydrazones and Isothiocyanates for the Selectivity Synthesis of 2-Amino-1,3,4-thiadiazoles and 1,2,4-Triazole-3-thiones

A photocatalytic chemodivergent reaction for the selectivity formation of C-S and C-N bonds in a controlled manner was proposed. The reaction medium, either neutral or acidic, is critical to dictate the formation of 2-amino-1,3,4-thiadiazoles and 1,2,4-triazole-3-thiones from isothiocyanates and hydrazones. This is a practical protocol to achieve the chemoselectivity under mild and metal-free conditions.