Enantioselective Synthesis of (+)-Providencin and Its Unexpected Regioisomer via a Biomimetic Norrish-Yang Cyclization from (-)-Bipinnatin E.
Org Lett
; 26(6): 1123-1127, 2024 02 16.
Article
en En
| MEDLINE
| ID: mdl-38096813
ABSTRACT
A biomimetic semisynthesis of the diterpenoid (+)-providencin (2) and the unexpected novel C14 regioisomer 3 was achieved by photoirradiation of the proposed biosynthetic cembranoid precursor (-)-bipinnatin E (1). The absolute configuration assignments of 1 and 2 by correlation were established by X-ray analysis. A combination of NOESY data and photochemical reaction results revealed that both C2 and C14 positions of the macrocycle (-)-1 are suitable for hydrogen abstraction, thus affording an explanation to the mixture of cyclobutane photoproduct isomers obtained by a Norrish-Yang cyclization. These results also support the proposed biosynthetic hypothesis describing the genuine photochemical transformation of (-)-1 into (+)-2, without refuting that both regioisomer products 2/3 might be artifacts of isolation.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Biomimética
/
Diterpenos
Idioma:
En
Revista:
Org Lett
Asunto de la revista:
BIOQUIMICA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos