Unusual amino acids IV. Asymmetric synthesis of thienylalanines
摘要:
(Z)-2-N-Acylamino-3-thienyl-acrylic acids and their esters were prepared by known procedures and hydrogenated to the corresponding optically active 2-N-acetyl(or benzoyl)-3-(2- or 3-thienyl)-alanines with optical yields up to 90 % using the rhodium complexes of ''PROPRAPHOS'' 6a,b and O,N-bis(diphenylphosphino)-2-exo-hydroxy,3-endo-methylamino-norbornane 6c as chiral catalysts, Recrystallization and deacylation of the obtained amino acid derivatives yields the optically pure hydrochlorides of the thienylalanines and the free amino acids.
Stereoselective Synthesis of 1,3-Diaminotruxillic Acid Derivatives: An Advantageous Combination of CH-<i>ortho</i>
-Palladation and On-Flow [2+2]-Photocycloaddition in Microreactors
作者:Elena Serrano、Alberto Juan、Angel García-Montero、Tatiana Soler、Francisco Jiménez-Márquez、Carlos Cativiela、M. Victoria Gomez、Esteban P. Urriolabeitia
DOI:10.1002/chem.201503742
日期:2016.1.4
The stereoselective synthesis of ε‐isomers of dimethyl esters of 1,3‐diaminotruxillic acid in three steps is reported. The first step is the ortho‐palladation of (Z)‐2‐aryl‐4‐aryliden‐5(4H)‐oxazolones 1 to give dinuclear complexes 2 with bridging carboxylates. The reaction occurs through regioselective activation of the ortho‐CH bond of the 4‐arylidene ring in carboxylic acids. The second step is