The structural motif of beta-amino acid derivatives is recurrent in biologically active compounds such as beta-lactam antibiotics1a,b,2 and beta-peptides1a,3a/d. In this last field, there is a need of new non proteinogenic beta-amino acids, and in particular those belonging to the beta2,3 class, since it is known that they could enhance the helical content when inserted in a peptide sequence as well as the resistance to peptidases. A very efficient protocol targeted on the synthesis of 2,3-diaryl-beta-amino acid derivatives was found using a TiCl4/TEA catalyzed Mannich-like reaction. The presence of an ortho coordinating heteroatom on arylacetic esters is of dramatic importance to modulate both the reactivity of the ester as well as the diastereoselection of the reaction. Both NMR and molecular dynamic studies clarified the stereochemical behavior of the above reaction. The use of phenylmenthyl moiety as chiral auxiliary allowed preparing the above compounds in high enantiopurity
Beta-2,3-Diaryl amminoacid via Mannich-like Reaction of Arylacetic ester/thioester: Chirality switching Induced by an Ayl-subtituted Ortho Heteroatom / A. Bonetti, F. Clerici, F. Foschi, S. Pellegrino, M. Penso, M.L. Gelmi. ((Intervento presentato al 35. convegno Convegno della Divisione di Chimica Organica - Società Chimica Italiana tenutosi a Sassari nel 2013.
Beta-2,3-Diaryl amminoacid via Mannich-like Reaction of Arylacetic ester/thioester: Chirality switching Induced by an Ayl-subtituted Ortho Heteroatom
A. BonettiPrimo
;F. Clerici;S. Pellegrino;M.L. Gelmi
2013
Abstract
The structural motif of beta-amino acid derivatives is recurrent in biologically active compounds such as beta-lactam antibiotics1a,b,2 and beta-peptides1a,3a/d. In this last field, there is a need of new non proteinogenic beta-amino acids, and in particular those belonging to the beta2,3 class, since it is known that they could enhance the helical content when inserted in a peptide sequence as well as the resistance to peptidases. A very efficient protocol targeted on the synthesis of 2,3-diaryl-beta-amino acid derivatives was found using a TiCl4/TEA catalyzed Mannich-like reaction. The presence of an ortho coordinating heteroatom on arylacetic esters is of dramatic importance to modulate both the reactivity of the ester as well as the diastereoselection of the reaction. Both NMR and molecular dynamic studies clarified the stereochemical behavior of the above reaction. The use of phenylmenthyl moiety as chiral auxiliary allowed preparing the above compounds in high enantiopurityPubblicazioni consigliate
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