2899-43-6Relevant articles and documents
Palladium-Catalyzed Allylic Alkylation of Aldimine Esters with Vinyl-Cyclopropanes to Yield α,α-Disubstituted α-Amino Acid Derivatives
Wang, Jiahua,Dai, Zonghao,Xiong, Cheng,Zhu, Jin,Lu, Jinrong,Zhou, Qingfa
supporting information, p. 5105 - 5111 (2019/11/11)
A synthetically useful approach for the synthesis of functionalized α, α-disubstituted α-amino acid derivatives via palladium-catalyzed 1,7 addition of readily available aldimine esters to vinylcyclopropanes is reported. This methodology was operated under mild conditions, affording α-allylic α-amino esters in good to excellent yields and excellent regio- and stereoselectivity. This transformation displays broad functional-group tolerance and enantioselective allylic alkylation has also been realized using a chiral phosphine ligand to provide the desired product. (Figure presented.).
Mimicking enzymatic transaminations: Attempts to understand and develop a catalytic asymmetric approach to chiral α-amino acids
Bachmann, Stephan,Knudsen, Kristian Rahbek,Jorgensen, Karl Anker
, p. 2044 - 2049 (2007/10/03)
Attempts are made to build a bridge between asymmetric catalysis and enzymatic reactions by mechanistic investigations and the development of a catalytic and enantioselective approach to amination of α-keto esters by primary amines catalyzed by chiral Lewis acids as a model for transamination enzymes. Different Lewis acids can catalyze the half-transamination of α-keto esters using primary amine nitrogen sources such as pyridoxamine and 4-picolylamine. The mechanistic studies of the Lewis-acid catalyzed half-transamination using deuterium-labelled compounds show the incorporation of deuterium atoms in several positions of the α-amino acid derivative, indicating that the enol of the α-keto ester plays an important role along the reaction path. The catalytic enantioselective reactions are dependent on the pKa-value of the solvent since enantioselectivities were only obtained in solvents with high pKa-values relative to methanol. However, stronger acidic conditions generally gave better yields, but poor enantioselectivities. A series of chiral Lewis acids were screened as catalysts for the enantioselective half-transamination reactions and moderate yields and enantioselectivities of up to 46% ee were obtained.
ENANTIOSELECTIVE HYDROLYSIS BY BAKER'S YEAST - II. ESTERS OF N-ACETYL AMINO ACIDS
Glaenzer, B. I.,Faber, K.,Griengl, H.
, p. 771 - 778 (2007/10/02)
D-N-Acetyl amino acid esters were obtained via enantioselective hydrolysis of their racemates by use of fermenting yeast.Evidence is given that proteinases are the enzymes involved.
