Synthesis of Dipeptides via Addition of N ‐(Nitroacetyl)amino‐Acid Derivatives to Michael Acceptors: Scope, Stereoselectivity, and Absolute Configuration
1992; Wiley; Volume: 75; Issue: 3 Linguagem: Inglês
10.1002/hlca.19920750306
ISSN1522-2675
AutoresAchamma Thomas, Sulur G. Manjunatha, S. RAJAPPA,
Tópico(s)Carbohydrate Chemistry and Synthesis
ResumoAbstract Michael addition of N ‐nitroacetyl derivatives 1 of proline esters using KF under phase‐transfer catalysis resulted in the formation of adducts 3–9 with chemical yields ranging from 40–90% ( Scheme ). Stereoselectivity of up to 51% was obtained on addition of benzyl N ‐(nitroacetyl)‐ L ‐prolinate ( 1a ). The absolute configuration at the newly created chiral centre was established in the case of 9 by carrying out a reductive acylation and comparing the product 10 with an authentic sample of ethyl N ‐( O 5 ‐ethyl N 2 ‐acetyl‐ L ‐glutam‐1‐yl)‐ L ‐prolinate ( L, L ‐ 10 ).
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