Efficient Rhodium-Catalyzed Multicomponent Reaction for the Synthesis of Novel Propargylamines.
[{Rh(μ-Cl)(H)2 (IPr)}2 ] (IPr = 1,3-bis-(2,6-diisopropylphenyl)imidazole-2-ylidene) was found to be an efficient catalyst for the synthesis of novel propargylamines by a one-pot three-component reaction between primary arylamines, aliphatic aldehydes, and triisopropylsilylacetylene. This methodology offers an efficient synthetic pathway for the preparation of secondary propargylamines derived from aliphatic aldehydes. The reactivity of [{Rh(μ-Cl)(H)2 (IPr)}2 ] with amines and aldehydes was studied, leading to the identification of complexes [RhCl(CO)IPr(MesNH2 )] (MesNH2 = 2,4,6-trimethylaniline) and [RhCl(CO)2 IPr]. The latter shows a very low catalytic activity while the former brought about reaction rates similar to those obtained with [{Rh(μ-Cl)(H)2 (IPr)}2 ]. Besides, complex [RhCl(CO)IPr(MesNH2 )] reacts with an excess of amine and aldehyde to give [RhCl(CO)IPr{MesNCHCH2 CH(CH3 )2 }], which was postulated as the active species. A mechanism that clarifies the scarcely studied catalytic cycle of A3 -coupling reactions is proposed based on reactivity studies and DFT calculations.
Departamento Química Inorgánica - ISQCH, Universidad de Zaragoza - CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain).
Laura
L
Rubio-Pérez
Departamento Química Inorgánica - ISQCH, Universidad de Zaragoza - CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain). miglesia@unizar.es.
Manuel
M
Iglesias
Departamento Química Física, Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain).
Julen
J
Munárriz
Departamento Química Física, Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain).
Victor
V
Polo
Departamento Química Inorgánica - ISQCH, Universidad de Zaragoza - CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain).
Jesús J
JJ
Pérez-Torrente
Departamento Química Inorgánica - ISQCH, Universidad de Zaragoza - CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain). oro@unizar.es.|King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261 (Saudi Arabia). oro@unizar.es.
Luis A
LA
Oro
CH activation; hydroalkynylation; multicomponent reactions; propargylamines; rhodium