A Rh(iii)-catalyzed C-H activation of indole at the C4-position leading to novel and switchable functionalization has been reported by employing a weakly co-ordinating COCF3 group as a directing group. An additive plays an important role in switching the selectivity between 1,4-addition products and Heck-type products. An acid additive led to the formation of 1,4-addition products whereas a base additive promotes the formation of Heck-type products. Deuteration studies and control experiments were helpful to propose the mechanism.

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A weakly coordinating carboxylate directing group assisted C−H activation with maleimides leading to novel and switchable decarboxylative Heck-type and [4 + 1] annulation products catalyzed by Rh(III) has been reported. In these reactions, solvents play a vital role in switching the selectivity. An aprotic solvent, THF, leads to the decarboxylative Heck-type product while the protic solvent, TFE, results in the [4 + 1] annulation product. The methodology shows high functional group tolerance.

Maleimides are not known to undergo oxidative‐Heck reaction because they lack a syn‐periplanar β‐hydrogen atom. Herein, we report a C−H activation‐based Mizoroki–Heck‐type reaction of maleimides using ketone as the directing group. The reaction utilizes a RhIII‐catalyst along with Ag2CO3 as the oxidant to carry out a base‐mediated formal β‐hydride elimination.

A weakly coordinating carbonyl-directed coupling of allyl alcohols at the C-4 position of indole derivatives under the C−H activation conditions catalyzed by Rh(III) is reported. This results in alkylation at the C-4 position of indole derivatives exclusively. The obtained product forms a tricyclic derivative under aldol reaction conditions, which can be a potential precursor for synthesizing a few alkaloid molecules such as ergot, hapalindole alkaloids, and related heterocyclic compounds.