Brønsted Base and Lewis Acid Cooperatively Catalyzed Asymmetric exo'-Selective [3 + 2] Cycloaddition of Trifluoromethylated Azomethine Ylides and Methyleneindolinones.
Org Lett
; 22(7): 2527-2531, 2020 Apr 03.
Article
en En
| MEDLINE
| ID: mdl-32202432
ABSTRACT
A Brønsted base and Lewis acid cooperatively catalyzed 1,3-dipolar cycloaddition is reported through chiral dinuclear zinc catalysts. An asymmetric exo'-selective [3 + 2] cycloaddition of CF3-containing N-unprotected isatin-derived azomethine ylides is realized. In the presence of 10 mol % of catalyst, azomethine ylides react efficiently with methyleneindolinones, giving a series of trifluoromethyl-substituted 2,3-pyrrolidinyl dispirooxindoles with highly enantio- (up to 99% ee) and exo'-selectivity (>201 dr). Up to four contiguous stereogenic centers, including two adjacent spiro quaternary stereocenters, are constructed in one step.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Org Lett
Asunto de la revista:
BIOQUIMICA
Año:
2020
Tipo del documento:
Article