Mild and selective base-free C–H arylation of heteroarenes: experiment and computation

Abstract

A mild and selective C–H arylation strategy for indoles, benzofurans and benzothiophenes is described.

Increasing Catalyst Efficiency in C−H Activation Catalysis

“…[12] as eries of methods for highly efficient direct arylation of ar ange of heteroarenes reaching impressive TONs up to 85 000 (Scheme 3). [15] Thus,t hese reactions might not involve actual CÀHa ctivation. [14] Likely,the arene coupling partner is introduced to the heterocycle by means of acarbopalladation as in the Heck olefin arylation.…”

Palladium‐catalyzed regioselective C2‐arylation of 5‐aminoindole

“…Although more mechanistic pathways on C─H activation reactions involving Pd(0) for the formation of C2 arylated indoles have been proposed, the cationic palladium‐proposed mechanisms have been much less . In this context, Sames and co‐workers showed a mechanism involving initial palladation at C3 followed by palladium migration to C2 via the Pd(II)/Pd(IV) pathways for C2 arylations of indoles .…”

Radical Arylation of Anilines and Pyrroles via Aryldiazotates

“…[36] For the arylation of anilines, which can be considered to be slightly less efficient aryl radicala cceptors than 3l,t he results presented in Ta ble 3s uggest that an excesso fa niline (5-10 equiv) relative to the diazonium salt is necessary to obtain useful yields ( % 50 %) of aminobiphenyls. RelatedP d-catalyzed transformations are able to provide good-to-high yields if the reactants are used in a1 :1 ratio.…”

“…RelatedP d-catalyzed transformations are able to provide good-to-high yields if the reactants are used in a1 :1 ratio. [36] For the arylation of anilines, which can be considered to be slightly less efficient aryl radicala cceptors than 3l,t he results presented in Ta ble 3s uggest that an excesso fa niline (5-10 equiv) relative to the diazonium salt is necessary to obtain useful yields ( % 50 %) of aminobiphenyls.…”