Rydfjord J, Skillinghaug B, Brandt P, Odell LR, Larhed M
Org. Lett. 19 (15) 4066-4069 [2017-08-04; online 2017-07-25]
We report a facile synthesis of 3-amidino indoles from indoles and cyanamides. The reaction is Pd(II)-catalyzed and proceeds via C-H bond activation of the indole in its 3-position followed by a 1,2-addition of the resulting indole-palladium σ-complex to a cyanamide, which provides the corresponding amidine. The preference for 4,5-diazafluoren-9-one (DAF) as the ligand is investigated using DFT calculations, and a plausible reaction pathway is presented.