Weakly coordinating tert-amide assisted Rh(iii)-catalyzed C4-cyanation of indoles: application in photophysical studies†

A rhodium(III)-catalyzed indole C4-selective cyanation is described using the bench-stable, user-friendly electrophilic cyanation agent N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) as a coupling partner. A suitably positioned weakly coordinating tert-amide group was utilized for this site selectivity. The developed protocol proceeded with a broad scope. [Cp*Rh(MeCN)(3)][SbF6] (2) was found to be an effective Rh(III) catalyst for this transformation. An initial study was carried out to know the photophysical properties of the C4-cyanated indole frameworks.

Automated summary

A rhodium(III)-catalyzed C4-selective cyanation of indole using N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) as a coupling partner is described. The protocol showed a broad scope and achieved site selectivity by utilizing a weakly coordinating tert-amide group. The photophysical properties of the C4-cyanated indole frameworks were studied.