Pd-catalyzed enantioselective synthesis of quaternary α-amino acid derivatives using a phenylalanine-derived P-chirogenic diaminophosphine oxide
摘要:
A Pd-catalyzed enantio selective synthesis of quaternary alpha-amino acid derivatives using a phenylalanine-derived P-chirogenic diaminophosphine oxide is described. Asymmetric allylic substitution using acyclic beta-keto esters with a nitrogen functional group at the alpha-carbon as prochiral nucleophiles proceeded in the presence of 5 mol % of Pd catalyst, 10 mol % of chiral diaminophosphine oxide 1j, BSA, and appropriate additives, affording the corresponding quaternary alpha-amino acid derivatives in excellent yield and in up to 92% ee. (c) 2007 Elsevier Ltd. All rights reserved.
Organocatalysis of asymmetric aldol reaction in water: comparison of catalytic properties of (S)-valine and (S)-proline amides
作者:A. S. Kucherenko、D. E. Siyutkin、R. R. Dashkin、S. G. Zlotin
DOI:10.1007/s11172-013-0132-z
日期:2013.4
(S)-Valine amides containing (S)- or (R)-α-phenylethyl substituents at N1 atom efficiently catalyze asymmetric aldol reactions between cyclic (heterocyclic) ketones and aromatic aldehydes in water, predominantly giving rise to the aldol anti-diastereomers in high yields (up to 98%) and enantiomeric excess (up to 94%).
Fast Amide Couplings in Water: Extraction, Column Chromatography, and Crystallization Not Required
作者:Sudripet Sharma、Nicklas W. Buchbinder、Wilfried M. Braje、Sachin Handa
DOI:10.1021/acs.orglett.0c01676
日期:2020.8.7
In the micelle of PS-750-M, the presence of 3 degrees amides from the surfactant proline linker mimics dimethylforma-mide, dimethylacetamide, and N-methyl-2-pyrrolidone. The resultant micellar properties enable extremely fast amide couplings mediated by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (without hydroxybenzotriazole), rather than expensive and specialized coupling agents. Conditions have been developed wherein products precipitate, and isolation by filtration completely avoids the use of organic solvent. This methodology is scalable and avoids product epimerization.
Enantioselective nickel-catalyzed conjugate addition of dialkylzinc to chalcones using chiral α-amino amides
作者:Jorge Escorihuela、M. Isabel Burguete、Santiago V. Luis
DOI:10.1016/j.tetlet.2008.09.120
日期:2008.11
A series of alpha-amino amides derived from natural amino acids (alanine, valine, phenylalanine, isoleucine, and phenylglycine) have been synthesized and fully characterized. Their Ni(II) complexes prepared from Ni(acac)(2) catalyze the enantioselective conjugate addition of diethylzinc to chalcones in high yields and in good enantioselectivities (up to 84%). The side chain of the amino acid and the substituents in the amide nitrogen govern the enantioselectivity of the catalytic process. (c) 2008 Elsevier Ltd. All rights reserved.