Synthesis of Polysubstituted Meta-Halophenols by Anion-Accelerated 2π-Electrocyclic Ring Opening.
Chemistry
; 27(42): 10941-10947, 2021 Jul 26.
Article
en En
| MEDLINE
| ID: mdl-34041800
Disrotatory - thermally allowed - 2π-electrocyclic ring-opening reactions require high temperatures to proceed. Herein, we report the first anion-accelerated 2π-electrocyclic ring opening of 6,6-dihalobicyclo[3.1.0]hexan-2-ones at low temperature to give the corresponding meta-halophenols in good to high yields (18 examples, 29-92 % yield, average: 65 %). Many of the phenols have unconventional substitution patterns and are reported here for the first time. Furthermore, the strength of the methodology was shown by the total synthesis of the densely functionalized phenolic natural product caramboxin (isolated as the lactam dehydrate). The reaction mechanism underlying the anion-acceleration was investigated in an ab initio study, which concluded that base-mediated proton abstraction anti to the concurrently departing endo-bromine was the initiating step in an overall concerted reaction mechanism leading directly to the meta-halophenol.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Lactamas
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Dinamarca
Pais de publicación:
Alemania