title: Expanding the substrate scope of Ugi five-center, four-component reaction U-5C-4CR): ketones as coupling partners for secondary amino acids.
abstract: Various symmetrical and unsymmetrical ketones were successfully coupled with secondary amino acids in the course of Ugi five-center, four-component reaction (U-5C-4CR), thus expanding the molecular diversity possible to be achieved by the reaction. The chemical yields depended on the degree of hindrance of the components employed and were satisfactory in view of possible steric interactions in the U-5C-4CR zwitterionic intermediate. The sense of diastereoinduction for reactions employing unsymmetrical ketones was examined by converting the resulting Ugi adducts into the corresponding rigid 2,6-diketopiperazine derivatives.
authors.affiliation: Department of Drug Technology and Pharmaceutical Biotechnology, Medical University of Warsaw, Banacha 1 Str., 02-097 , Warsaw, Poland, maciej.dawidowski@wum.edu.pl.
authors.forename: Maciej
authors.initials: M
authors.lastname: Dawidowski
authors.forename: Sławomir
authors.initials: S
authors.lastname: Sobczak
authors.forename: Marcin
authors.initials: M
authors.lastname: Wilczek
authors.forename: Artur
authors.initials: A
authors.lastname: Kulesza
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Turło
mesh_terms: D007098:Imino Acids / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D007098:Imino Acids; D007659:Ketones