Ti/Ni-mediated inter- and intramolecular conjugate addition of aryl and alkenyl halides and triflates.
In this work, we show that the unique combination of a nickel catalyst and Cp2TiCl allows the direct conjugate addition of aryl and alkenyl iodides, bromides, and to a lesser extent, chlorides and triflates to α,β-unsaturated carbonyls at room temperature, without requiring the previous formation of an organometallic nucleophile. The reaction proceeds inter- and intramolecularly with good functional group compatibility, which is key for the development of free protecting group methodologies. Carbo- and heterocycles of five- and six-membered rings are obtained in good yields. Moreover, some insights about the mechanism involved have been obtained from cyclic voltammetry, UV-vis, and HRTEM measurements.
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Granada , E-18071 Granada, Spain.
Irene R
IR
Márquez
Delia
D
Miguel
Alba
A
Millán
M Luisa
ML
Marcos
Luis
L
Álvarez de Cienfuegos
Araceli G
AG
Campaña
Juan M
JM
Cuerva