%0 Journal Article %A Ventosa-Andrés, Pilar %A Hradilová, Ludmila %A Krchňák, Viktor %D 2014 %T Privileged Structures as Peptide Backbone Constraints: Polymer-Supported Stereoselective Synthesis of Benzimidazolinopiperazinone Peptides %U https://acs.figshare.com/articles/journal_contribution/Privileged_Structures_as_Peptide_Backbone_Constraints_Polymer_Supported_Stereoselective_Synthesis_of_Benzimidazolinopiperazinone_Peptides/2274688 %R 10.1021/co500023k.s001 %2 https://acs.figshare.com/ndownloader/files/3910714 %K Conventional %K functionalized %K cyclization %K target compounds %K synthese %K acid %K integrity %K microwave conditions %K Privileged Structures %K acylation %K synthesis %K peptide backbone %K tandem %K Peptide Backbone Constraints %K Significant epimerization %K stereocontrol %K constraint %K Stereoselective %K efficiency %K stereogenic center %K Benzimidazolinopiperazinone PeptidesA %K Synthesi %K scaffold %X A molecular scaffold comprising a privileged structure was designed and synthesized to serve as a peptide backbone conformational constraint. The synthesis of highly functionalized 2,3,10,10a-tetrahydrobenzo­[4,5]­imidazo­[1,2-a]­pyrazin-4­(1H)-ones on a solid-phase support was performed via a tandem N-acyl-N-aryliminium ion cyclization–nucleophilic addition reaction. The synthesis proceeded with full stereocontrol of the newly formed stereogenic center. Conventional and microwave-assisted syntheses were compared with respect to efficiency and the optical integrity of the target compounds. Significant epimerization was observed during acylation with (S)- and (R)-2-bromopropionic acids under microwave conditions. %I ACS Publications