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

This study describes a rhodium(III)-catalyzed indole C4-selective cyanation using the bench-stable and user-friendly electrophilic cyanation agent N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) as a coupling partner. The selective site was achieved by utilizing a suitable weakly coordinating tert-amide group. The protocol developed in this study has a wide scope and [Cp*Rh(MeCN)(3)][SbF6](2) was identified as an effective Rh(III) catalyst. The photophysical properties of the C4-cyanated indole frameworks were also investigated.