Enantioselective Synthesis and Racemization of (-)-Sinoracutine.
Angew Chem Int Ed Engl
; 56(3): 897-901, 2017 01 16.
Article
en En
| MEDLINE
| ID: mdl-27990734
ABSTRACT
Sinoracutine is a recently isolated alkaloid with unusual stereochemical and biological properties. It features an unprecedented tetracyclic 6/6/5/5 skeleton that bears an N-methylpyrrolidine ring fused to a cyclopentenone. Interestingly, both enantiomers of sinoracutine have been independently isolated from the same plant, yet the molecule does not appear to occur as a racemate. Here, we present a short synthesis of (-)-sinoracutine that relies on a highly diastereoselective Pauson-Khand reaction and a Mandai-Claisen reaction to install the quaternary stereocenter. Our work establishes the absolute configuration of the levorotatory isomer and suggests that the optical purity of sinoracutine varies in nature due to its gradual racemization. Experimental evidence supports this proposal, and a plausible mechanism for the racemization is provided.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Pirrolidinas
/
Ciclopentanos
/
Alcaloides
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2017
Tipo del documento:
Article
País de afiliación:
Alemania