title: Metal-free 1,5-regioselective azide-alkyne [3+2]-cycloaddition.
abstract: [3+2]-cycloaddition reactions of aromatic azides and silylated alkynes in aqueous media yield 1,5-disubstituted-4-(trimethyl-silyl)-1H-1,2,3-triazoles. The formation of the 1,5-isomer is highly favored in this metal-free cycloaddition, which could be proven by 1D selective NOESY and X-ray investigations. Additionally, DFT calculations corroborate the outstanding favoritism regarding the 1,5-isomer. The described method provides a simple alternative protocol to metal-catalyzed "click chemistry" procedures, widening the scope for regioselective heavy-metal-free synthetic applications.
authors: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany.
authors: Florian
authors: F
authors: Kloss
authors: Uwe
authors: U
authors: Köhn
authors: Burkhard O
authors: BO
authors: Jahn
authors: Martin D
authors: MD
authors: Hager
authors: Helmar
authors: H
authors: Görls
authors: Ulrich S
authors: US
authors: Schubert
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization; D008670:Metals; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory; D013237:Stereoisomerism; D014230:Triazoles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D001386:Azides; D008670:Metals; D014230:Triazoles