A photochemical approach to phenylalanines and related compounds by alkylation of glycine
作者:Haydn S Knowles、Keith Hunt、Andrew F Parsons
DOI:10.1016/s0040-4020(01)00783-9
日期:2001.9
Phenylalanines can be prepared on UV photolysis of protected glycines in the presence of di-tert-butylperoxide, substituted toluenes and the photosensitiser benzophenone. These reactions, which lead to highly selective mono-alkylation at the α-position of glycines, involve coupling of captodative α-glycine radicals with benzyl radicals. This method can be used to selectively alkylate a variety of
Nucleophilic Iron Catalysis in Transesterifications: Scope and Limitations
作者:Silja Magens、Bernd Plietker
DOI:10.1021/jo1004636
日期:2010.6.4
The ester bond is one of the most common structural motifs found in nature. Apart from the condensation between an acid and an alcohol, transesterifications represent another mechanistic alternative for the preparation of this compound class. The present paper summarizes our most recent investigations in this field, using nucleophilic iron complexes as catalysts for transesterifications under neutral conditions. This new type of metal catalyst complements the existing methodologies, which rely on Lewis acidic metal complexes. Investigations on scope and limitations, stereochemical course, and chemoselectivities will be presented.
Synthesis of diastereo- and enantiomerically pure α-amino-γ-oxo acid esters by reaction of acyliminoacetates with enamines derived from 6-membered ketones
A new efficient diastereo- and enantioselective synthesis of α-amino-γ-oxo acid esters by reaction of acyliminoacetates with enamines is described. By employing the concept of double stereodifferentiation, complete asymmetric induction (de ≧99.9%) for the C-C bond formation is obtained. Desulphurization of a sulphur containing product leads to the corresponding acyclic amino acid derivatives. The