2005
Susana Rojas-Lima, Omar Téllez-Zenteno, Heraclio López-Ruiz, Lizeth Loubet-González, and Alejandro Alvarez-Hernandez. 3-Benzoyl-2-isopropyl-4-alkyloxazolidin-5-ones as Efficient and Inexpensive Sources of Enantiopure a,a-Dialkyl-a-amino Acids and a,ß-Dialkyl-a,ß-diaminopropionic Acids Heterocycles, 2005, 65, 59-75. ISNN 1881-0942. The Japan Institute of Heterocyclic Chemistry. Japón.
Abstract
It is shown that the 3-benzoyl-2-isopropyl-4-alkyloxazolidin-5-ones (12), derived from isobutyraldehyde and ?-amino acids are as efficient as, but more economical than, the corresponding tert-butyl compounds (9), as sources of enantiopure ?,?-dialkylated ?-amino acids (e.g., 21-23). In the absence of alkylating agents, the anions of (2R,4S)-12 and its enantiomer undergo a fragmentation-recombination process to generate (1S,2R,4S)-N-[1-(3-benzoyl- 2-isopropyl-4-methyl-5-oxo-oxazolidin-4-yl)-2-methylpropyl]benzamide ((1S, 2R,4S)-20), and its enantiomer. Acidic methanolysis of these condensation products provides access to ?,?-dialkylated ?,?-diaminopropionic acids [e.g., (2S,3S)-2,3-bisbenzoylamino-2,4-dimethylpentanoic acid methyl ester ((2S,3S)-24)).
A practical access to acyl radicals from acyl hydrazides
Study of the reactivity of squarylferrocenes. Addition of amines and aminoesters
Et3, and efficient Mediator for Xanthate Transfer Based Radical Processes.
Synthesis and Structures of some Lithium and Sodium (Aminoalcoholato)hydrido Aluminates
Diastereoselective Synthesis of Spiro-?-lactams via Staudinger Reactio