Palladium-mediated functionalization of heteroaromatic cations: comparative study on quinolizinium cations.
An efficient palladium-catalyzed cross-coupling reaction on heteroaromatic cations is described. A comparative study of the Stille and Suzuki reactions shows that only the Stille reaction is able to produce an efficient C-C bond formation between any of the four isomeric bromoquinolizinium bromides and a variety of stannanes. In the presence of the catalysts Pd(PPh3)4 or Pd2(dba)3P(o-Tol)3, vinyl, ethynyl, aryl, and heteroaryl groups are successfully incorporated into the quinolizinium system in satisfactory yields under mild reaction conditions. This procedure represents a marked improvement on the functionalization of this class of heteroaromatic cation.
García-Cuadrado
Domingo
D
Departamento de Química Organica, Universidad de Alcala, 28871-Alcala de Henares, Madrid, Spain.
Cuadro
Ana M
AM
Barchín
Bernardo M
BM
Nuñez
Ana
A
Cañeque
Tatiana
T
Alvarez-Builla
Julio
J
Vaquero
Juan J
JJ