2024-03-28T11:19:02Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1338202016-10-20T09:20:11Zcom_10261_52707com_10261_5col_10261_52708
Rhodium(I)-N-heterocyclic carbene catalyst for selective coupling of N-vinylpyrazoles with alkynes via C-H activation
Azpíroz, Ramón
Rubio-Pérez, Laura
Giuseppe, Andrea di
Passarelli, Vincenzo
Lahoz, Fernando J.
Castarlenas, Ricardo
Pérez-Torrente, Jesús J.
Oro, Luis A.
Diputación General de Aragón
ARAID Foundation
Consejo Nacional de Ciencia y Tecnología (México)
Ministerio de Economía y Competitividad (España)
C−H activation
C−C coupling
N-heterocyclic carbene
Pyrazole
Rhodium
The complex [Rh(μ-Cl)(IPr)(η2-coe)]2 {IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-carbene, coe = cis-cyclooctene} efficiently catalyzes the coupling of alkynes and N-vinylpyrazole via C–H activation, leading to Markovnikov-selective butadienylpyrazole derivatives under mild conditions. A straightforward approach to cross-conjugated acyclic trienes is also operative through a one-pot alkyne dimerization-hydrovinylation tandem reaction. The proposed mechanism involves C–H activation of vinylpyrazole directed by nitrogen coordination to the metallic center. Subsequent alkyne coordination, insertion, and reductive elimination steps lead to the coupling products. Several key intermediates participating in the catalytic cycle have been detected and characterized, including a κ-N, η2-C═C coordinated vinylpyrazole complex and a RhIII-hydride-alkenyl species resulting from the C–H activation of the vinylpyrazole.
2016-06-21T10:11:45Z
2016-06-21T10:11:45Z
2014
2016-06-21T10:11:45Z
artículo
ACS Catalysis 4(12): 4244-4253 (2014)
http://hdl.handle.net/10261/133820
10.1021/cs501366q
http://dx.doi.org/10.13039/501100003141
http://dx.doi.org/10.13039/501100003329
eng
Postprint
http://dx.doi.org/10.1021/cs501366q
Sí
openAccess
American Chemical Society