Synthesis of cyclobakuchiols A, B, and C by using conformation-controlled stereoselective reactions.
Chemistry
; 20(1): 272-8, 2014 Jan 03.
Article
em En
| MEDLINE
| ID: mdl-24273103
ABSTRACT
Cyclohexanone with the pMeOC6H4 and CH2=C(Me) substituents at the C3 and C4-positions was prepared from (+)-ß-pinene and converted to the allylic picolinate by a Masamune-Wittig reaction followed by reduction and esterification. Allylic substitution of this picolinate with Me2CuMgBr·MgBr2 in the presence of ZnI2 proceeded with γ regio- and stereoselectively to afford the quaternary carbon center on the cyclohexane ring with the CH2=CH and Me groups in axial and equatorial positions, respectively. This product was converted to cyclobakuchiol A by demethylation and to cyclobakuchiol C by epoxidation of the CH2=C(Me) group. For the synthesis of cyclobakuchiol B, the enantiomer of the above cyclohexanone derived from (-)-ß-pinene was converted to the cyclohexane-carboxylate, and the derived enolate was subjected to the reaction with CH2=CHSOPh followed by sulfoxide elimination to afford the intermediate with the quaternary carbon center with MeOC(=O) and CH2=CH groups in axial and equatorial positions. The MeOC(=O) group was transformed to the Me group to complete the synthesis of cyclobakuchiol B.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenóis
/
Cicloexanos
/
Anti-Inflamatórios
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article