Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines.
Angew Chem Int Ed Engl
; 56(48): 15358-15362, 2017 11 27.
Article
em En
| MEDLINE
| ID: mdl-29044902
ABSTRACT
N-Boc ketimines derived from pyrazolin-5-ones were explored to develop an unprecedented domino aza-Friedel-Crafts/N,O-acetalization reaction with 2-naphthols. The novel method requires a catalyst loading of only 0.5â
mol % of a bifunctional squaramide catalyst, is scalable to gram amounts, and provides a new series of furanonaphthopyrazolidinone derivatives bearing two vicinal tetra-substituted stereogenic centers in excellent yields (95-98 %) and stereoselectivity (>991 d.r. and 97-98 % ee). A different reactivity was observed in the case of 1-naphthols and other electron-rich phenols, which led to the aza-Friedel-Crafts adducts in 70-98 % yield and 47-98 % ee.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Alemanha