Enantioselective Michael Addition/Cyclization/Desymmetrization Sequence of Prochiral Cyclic Hemiacetals and Nitroolefins: Synthesis of Chiral Oxygen-Bridged Bicyclic Compounds.
Org Lett
; 24(50): 9254-9258, 2022 12 23.
Article
em En
| MEDLINE
| ID: mdl-36512320
ABSTRACT
The organocatalytic enantioselective Michael addition of functionalized prochiral cyclic hemiacetals and nitroolefins has been developed under cooperative enamine and hydrogen bond catalysis. The obtained chiral hemiacetal intermediates could be used in the subsequent diastereocontrolled cyclization/desymmetrization divergent process to access (1) 9-oxabicyclo[3.3.1]nonane or 8-oxabicyclo[3.2.1]octane frameworks via oxocarbenium ion-mediated Friedel-Crafts cyclization, and (2) 2,9-dioxabicyclo[3.3.1]nonane frameworks via intramolecular nucleophilic cyclization. Experimental results suggest that there is neighboring group participation controlling the diastereoselectivities of the desymmetrization process.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Oxigênio
/
Compostos Bicíclicos com Pontes
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article