C2-Alkylation and Alkenylation of Indoles Catalyzed by a Low-Valent Cobalt Complex in the Absence of Reductant

Brendan J. Fallon , Etienne Derat (1) , Muriel Amatore (2) , Corinne Aubert (1) , Fabrice Chemla (1) , Franck Ferreira (1) , Alejandro Perez-Luna (1) , Marc Petit (1)

1 IPCM - Institut Parisien de Chimie Moléculaire
2 DCPH - Laboratoire Hétéroéléments et Coordination

Herein an extremely versatile, well-defined, low-valent cobalt catalyst [Co(PMe3)(4)] capable of intermolecular and intramolecular imine-directed C2-alkylation and alkenylation of indoles is reported. The reaction proceeds in the absence of reducing agents or additives, affording a range of substituted indoles and dihydropyrroloindoles in high yields and regioselectivities. With the aid of deuterium labeling studies and DFT (Density Functional Theory) calculations, a mechanism is proposed that is based on a Ligand-to-Ligand Hydrogen Transfer pathway.

Domaines: Chimie organique

Brendan J. Fallon, Etienne Derat, Muriel Amatore, Corinne Aubert, Fabrice Chemla, et al.. C2-Alkylation and Alkenylation of Indoles Catalyzed by a Low-Valent Cobalt Complex in the Absence of Reductant. Organic Letters, 2016, 18 (9), pp.2292-2295. ⟨10.1021/acs.orglett.6b00939⟩. ⟨hal-01397956⟩