Cooperative Catalysis-Enabled Asymmetric α-Arylation of Aldehydes Using 2-Indolylmethanols as Arylation Reagents.
J Org Chem
; 83(9): 5027-5034, 2018 05 04.
Article
en En
| MEDLINE
| ID: mdl-29649365
ABSTRACT
A catalytic asymmetric α-arylation of aldehydes using 2-indolylmethanols as arylation reagents has been established. This reaction was enabled by a cooperative catalytic system consisting of a gold complex, a Brønsted acid, and a chiral amine, which have a synergistic effect in the reaction process. By using this strategy, a series of α-arylation products of aldehydes were generated in overall acceptable yields and good enantioselectivities (up to 69%, 919 er). The control experiments demonstrated that the addition of PPh3AuCl as a gold complex was helpful to improve the yield, and trifluoroacetic acid as a Brønsted acid played a crucial role in the reaction by promoting the generation of carbocation and chiral enamine intermediates, which are two key intermediates of the asymmetric α-arylation reaction. In addition, the enantioselectivity of the reaction was mainly controlled by the chiral amine catalyst via forming a chiral enamine intermediate. This reaction has not only provided a useful protocol for catalytic asymmetric α-arylation of aldehydes but also enriched the research contents of 2-indolylmethanol-involved reactions and asymmetric cooperative catalysis.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Año:
2018
Tipo del documento:
Article
País de afiliación:
China