Asymmetric synthesis of diastereomerically and enantiomerically pure α-amino-γ-nitro carboxylic esters via Michael addition of the titanated bislactim ether of cyclo (-L-Val-Gly-) to nitroolefines
1992; Elsevier BV; Volume: 48; Issue: 27 Linguagem: Inglês
10.1016/0040-4020(92)80011-4
ISSN1464-5416
AutoresKarla Busch, Ulrich Groth, Wulf Kühnle, Ulrich Schöllkopf,
Tópico(s)Fluorine in Organic Chemistry
ResumoThe titanated bislactim ethers of cyclo(-L-Val-Gly-) 3 and 7 were added highly diastereoselectively in a 1,4-fashion to the nitro olefines 4 yielding the nitro compounds 5. Upon acidic hydrolysis these nitro compounds 5 afforded the α-amino-γ-nitro acid esters 12, which can be hydrogenated to the lactames 14. The oxazoline derivatives 17 were obtained via their nitrile oxides 15 in a subsequent dipolar (2+3)-cycloaddition. These derivatives 17 can be hydrolyzed to the oxazoline containing amino acid esters 18.
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