Stereoselective Approach to Hydroxyalkyl-1,2,3-triazoles Containing Cyclooctane Core and Their Use for CuAAC Catalysis

Abstract

1,2,3-Triazoles bearing additional functional groups have found applications as the ligands in catalysis of a broad scope of reactions, synthesis of transition metals complexes for various practicable purposes, and design of metal-based drugs. Triazolyl ligands accelerating CuAAC reactions, such as TBTA and TTTA, are nowadays commonly used in organic synthesis, and the search for novel ligands with a less complicated structure represents an important task. In the present work a series of hydroxyalkyltriazoles, containing a cyclooctane core, were synthesized via cycloaddition of readily available individual diastereomers of azidoalcohols or diazidodiols with phenylacetylene. The obtained hydroxyalkyltriazoles were probed as ligands for CuAAC reactions of benzyl azide with acetylenes, and 1-[(4-phenyl-1H-1,2,3-triazol-1-yl)methyl]cyclooctanol was demonstrated to act as an effective ligand for these processes. The complex salt of the abovementioned triazole and CuCl2 was readily obtained. According to X-ray diffraction analysis data, the complex contained two molecules of triazole, in which only N1-atoms of the triazole ring acted as coordination centers. Such a molecular structure correlates well with the efficiency of 1-[(4-phenyl-1H-1,2,3-triazol-1-yl)methyl]cyclooctanol as a ligand in CuAAC reactions: it is able to coordinate copper ions and, at the same time, it forms a sufficiently labile complex to not withdraw copper ions from the catalytic cycle.

Six polyoxotungstate-based transition metal compounds for electrochemical capacitor application and a comparative analysis of factors affecting capacitances

“…Consequently, scientists have been motivated to explore alternative candidates. Meanwhile, transition metal complexes, known for their high specific surface area, adjustable pore size and good thermal stability, have found extensive application prospects in magnetism, [29][30][31][32][33] catalysis, [34][35][36] luminescence, 34,37,38 electrochemical sensors, [39][40][41] etc. As a result, an encouraging strategy of incorporating POMs into transition metal complexes (TMCs) to build POM-based transition metal complexes (POM-TMCs) was put forward.…”