Metal-free 1,5-regioselective azide-alkyne [3+2]-cycloaddition

Chem Asian J. 2011 Oct 4;6(10):2816-24. doi: 10.1002/asia.201100404. Epub 2011 Aug 31.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemistry*
  • Azides / chemistry*
  • Crystallography, X-Ray
  • Cyclization
  • Metals
  • Models, Molecular
  • Molecular Structure
  • Quantum Theory
  • Stereoisomerism
  • Triazoles / chemical synthesis*
  • Triazoles / chemistry

Substances

  • Alkynes
  • Azides
  • Metals
  • Triazoles