Selective C-H bond functionalization of unprotected indoles bydonor-acceptor carbene insertion

D. Pizarro, L. Moran-Gonzalez, I. Gonzalez-Fernandez, F. Maseras, M. R. Fructos, P. J. Perez Adv. Synth. Catal. 10.1002/adsc.202300252

Copper catalysts containing alkoxydiaminophosphine (ADAP) ligand catalyze the selective C3-H functionalization of unprotected indoles upon carbene transfer from donor-acceptor diazo compounds, the N-H bond remaining unaltered during the transformation. Mechanistic studies, including DFT calculations, allows proposing the existence of two competitive pathways, none of the occurring through the formation of cyclopropane intermediates, at variance with previously reported systems.