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.

Department of Organic Chemistry Institute of Molecular and Translational Medicine Faculty of Science Palacký University 17 Listopadu 12 771 46 Olomouc Czech Republic

Citace poskytuje Crossref.org

Regioselective Cyclic Iminium Formation of Ugi Advanced Intermediates: Rapid Access to 3,4-Dihydropyrazin-2(1H)-ones and Other Diverse Nitrogen-Containing Heterocycles