Fluorescent Diarylindoles by Palladium‐Catalyzed Direct and Decarboxylative Arylations of Carboxyindoles

Abstract

Simple and brilliant: 1-Substituted 1H-indole-2-carboxylic acids efficiently undergo successive diarylation accompanied by C-H bond cleavage and decarboxylation upon treatment with aryl bromides in the presence of a palladium catalyst system to afford fluorescent 2,3-diarylindoles. This facile synthetic method provides a highly efficient blue emitter with a quantum yield of 0.97 in the solid state (see scheme).

Transition‐Metal‐Catalyzed Direct Arylation of (Hetero)Arenes by CH Bond Cleavage

“…[137] These decarboxylative arylations and related processes were previously exploited by Miura and co-workers for intriguing sequential arylations. In a representative example, a sequence consisting of a direct arylation and a decarbamoylation allowed for the preparation of triarylated product 173 (Scheme 67).…”

Übergangsmetallkatalysierte direkte Arylierungen von (Hetero)Arenen durch C‐H‐Bindungsbruch

“…Die Methode bot Zugang zu substituierten Indolen mit wertvollen optischen Festkörpereigenschaften (Schema 66). [137] Zu erwähnen ist, dass Miura gesetzt hatten. Beispielsweise gelang mit einer Reaktionsfolge aus direkter Arylierung und Decarbamoylierung die Herstellung der triarylierten Verbindung 173 (Schema 67).…”

Low‐Temperature Ag/Pd‐Catalyzed Decarboxylative Cross‐Coupling of Aryl Triflates with Aromatic Carboxylate Salts

“…[5] These transformations have reached impressive performance levels in terms of selectivity, functional group tolerance, and yield. [6] However, their practical applicability is still somewhat limited by the high reaction temperatures currently required in the decarboxylation step. [7] The redox-neutral decarboxylative cross-couplings developed in our group allow a regioselective C À C bond formation between aryl, heteroaryl, or acyl carboxylates and aryl halides to give biaryls or aryl ketones without resorting to stoichiometric amounts of organometallic reagents.…”