NNN Pincer Ru(II)-Complex-Catalyzed α-Alkylation of Ketones with Alcohols.
J Org Chem
; 83(7): 3657-3668, 2018 04 06.
Article
em En
| MEDLINE
| ID: mdl-29533663
ABSTRACT
A series of novel ruthenium(II) complexes supported by a symmetrical NNN ligand were prepared and fully characterized. These complexes exhibited good performance in transfer hydrogenation to form new C-C bonds using alcohols as the alkylating agents, generating water as the only byproduct. A broad range of substrates, including (hetero)aryl- or alkyl-ketones and alcohols, were well tolerated under the optimized conditions. Notably, α-substituted methylene ketones were also investigated, which afforded α-branched steric hindrance products. A potential application of α-alkylation of methylene acetone to synthesize donepezil was demonstrated, which provided the desired product in 83% yield. Finally, this catalytic system could be applied to a one-pot double alkylation procedure with sequential addition of two different alcohols. The current protocol is featured with several characteristics, including a broad substrate scope, low catalyst (0.50 mol %) loadings, and environmental benignity.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article