131791-76-9Relevant academic research and scientific papers
Preparation and Assignment of Configuration of 1-Benzoyl-(2S)-tert-butyl-3-methyl-perhydropyrimidin-4-one. Useful Starting Material for the Enantioselective Synthesis of α-Substituted β-Amino Acids
Juaristi, Eusebio,Quintana, Delia
, p. 723 - 726 (1992)
(S)-Asparagine, an inexpensive β-amino acid was converted into the title heterocycle (+)-1 in very good overall yield.The highly selective trans methylation of (+)-1-Li, and the hydrolysis of the resulting adduct afforded (R)-α-methyl-β-alanine, allowing the assignment of the (S) configuration in (+)-1.
Enantioselective synthesis of β-amino acids. 7. Preparation of enantiopure α-substituted β-amino acids from 1-benzoyl-2(S)-tert-butyl-3-methylperhydropyrimidin-4-one
Juaristi, Eusebio,Quintana, Delia,Balderas, Margarita,Garcia-Perez, Enrique
, p. 2233 - 2246 (2007/10/03)
Inexpensive natural α-amino acid L-asparagine was efficiently converted to either (R)- or (S)-α-alkylated β-amino acids in enantiomerically pure state. The key intermediate in this protocol is the enantiopure N,N-acetal pyrimidinone (S)-1, a masked chiral derivative of β-alanine.
Enantiomerically pure dihydropyrimidinones as reagents and auxiliaries for asymmetric synthesis
Chu, Kent S.,Negrete, George R.,Konopebki, Joseph P.,Lakner, Frederick J.,Woo, Nam-Tae,Olmstead, Marilyn M.
, p. 1800 - 1812 (2007/10/02)
We report herein full experimental details of the synthesis, structure, and reactivity of (R)- and (S)-2-tert-butyl-l-carbomethoxy-2,3-dihydropyrimidin-4(lH)-one (1). The synthesis employs asparagine as the starting material and provides 1 in 55% yield without the need for Chromatographic purification. The structure of 1, as determined by X-ray crystallographic analysis, demonstrates significant pyramidalization at the C4 (carbonyl) and N1 centers, with little evidence of conjugation of Nl with the αβ,-unsaturated (vinylogous urea) system. In contrast, compound 11 [2-tert-butyl-3-((S)-O-methylmandeloyl)-2,3-dihydropyrimidin-4(lH)-one] shows strong coupling of Nl to the αβ,-unsaturated system, as evidenced by changes in bond lengths and torsional angles. Compound 1 has proven useful as a reagent for the synthesis of enantiomerically pure β-aryl-β-amino acids. The key step in this protocol is the palladium-catalyzed conjugate addition of aryl iodides to 1. Evidence is presented to support a mechanism for this reaction that involves an unprecedented transannular hydride transfer into the palladium coordination sphere. In additional experiments, 1 has been employed as an auxiliary for the synthesis of enantiomerically pure α-substituted carboxylic acids. The crystalline properties of 1 and many of its derivatives allow for simplified purification procedures to be utilized.
Self-Reproduction of Chirality. Asymmetric Synthesis of β-Aryl-β-amino Acids from Enantiomerically Pure Dihydropyrimidinones
Konopelski, Joseph P.,Chu, Kent S.,Negrete, George R.
, p. 1355 - 1357 (2007/10/02)
Enantiomerically pure dihydropyrimidinone 1 reacts with aryl iodides in the presence of catalytic amounts of Pd(OAc)2 and added phosphine to afford dihydropyrimidinone 4, in which a formal conjugate addition of the aryl group to the α,β-unsaturated system
