- Palladium-Catalyzed Suzuki-Miyaura, Heck and Hydroarylation Reactions on (-)-Levoglucosenone and Application to the Synthesis of Chiral γ-Butyrolactones
-
The chiral pool material (-)-levoglucosenone (6,8-dioxabicyclo[3.2.1]oct-2-en-4-one, LGO) has been substituted by using a series of Pd-mediated cross-coupling reactions. Iodination of LGO followed by Suzuki-Miyaura cross-coupling reaction with boronic acids by employing the Buchwald ligand SPhos with Pd(OAc)2 afforded 3-aryl derivatives in excellent yields. Selective Heck arylation reaction at the 2-position was achieved with aryl iodides with K3PO4 as base and SPhos ligand with Pd(OAc)2 (1-5 mol-%). A selective hydroarylation reaction (formal conjugate addition) was developed by using the same aryl iodides, benzyldiethylamine, Pd(OAc)2, and P(o-tol)3. The products were converted, either directly or after alkene reduction, through a Baeyer-Villiger oxidation into chiral 3- and 4-substituted 5-(hydroxymethyl)dihydrofuran-2(3H)-ones. Three new cross-coupling approaches to the derivatization of levoglucosenone are described and the products converted into butyrolactones.
- Stockton, Kieran P.,Merritt, Christopher J.,Sumby, Christopher J.,Greatrex, Ben W.
-
-
Read Online
- CNS-active pyrans: Amine- and aryl-substituted 6,8-dioxabicyclo-octanes
-
The amin- and phenyl substituted 6,8-dioxabicyclooctanes 10 and 11 show distinct CNS-activities. Intensity and profile depend on the type of amine and the stereochemistry of the products. Therefore, we have synthesized 6,8-dioxabicyclooctanes with differe
- Eiden,Denk,Hofner
-
p. 405 - 412
(2007/10/02)
-