Chemo- and regioselective click reactions through nickel-catalyzed azide–alkyne cycloaddition

Abstract

Nickel-catalyzed [3 + 2] cycloaddition reactions of unsymmetrical alkynes and organic azides afford substituted 1,2,3-triazoles with high levels of chemo- and regioselectivity.

Ni–rGO–zeolite nanocomposite: an efficient heterogeneous catalyst for one-pot synthesis of triazoles in water

“…We found that the present heterogeneous catalytic system offers certain advantages like easy preparation from cheap and sustainable materials, stable at room temperature, high catalytic efficiency in aqueous medium, regioselective formation of 1,4-disubstituted-1,2,3triazoles, recovery by simple filtration and recyclability. As compared to previously reported very few homo-and heterogeneous Ni-based catalysts used in AAC, [13][14][15][16] the present catalytic process using Ni-rGO-zeolite follows three-component cycloaddition, which is more advantageous over two-component cycloaddition process because the former avoids an extra step of making unstable organyl azides (Scheme 1).…”

“…The nickel (Ni) catalyzed azide alkyne [3+2] cycloaddition (NiAAC) has been rarely explored and literature reports reveal only a few Ni-based catalysts employed in AAC. [13][14][15][16] While the use of Raney nickel leads to both 1,4-and 1,5-disubstituted cyclo-adducts, 13 the other ligand-specific and expensive catalytic system (Cp2Ni-Xantphos) can be used for both terminal and internal alkynes preferentially forming 1,5-disubstituted triazole. 14,15 Moreover, the actual catalyst in this case is Ni(Xantphos)2, which is generated in situ and not recoverable.…”

“…[13][14][15][16] While the use of Raney nickel leads to both 1,4-and 1,5-disubstituted cyclo-adducts, 13 the other ligand-specific and expensive catalytic system (Cp2Ni-Xantphos) can be used for both terminal and internal alkynes preferentially forming 1,5-disubstituted triazole. 14,15 Moreover, the actual catalyst in this case is Ni(Xantphos)2, which is generated in situ and not recoverable. 15 Another heterogeneous Ni catalyst is based on triazole linked organic polymer (Ni-TLOP), which acts as a photocatalyst in AAC under visible light induced condition.…”

“…14,15 Moreover, the actual catalyst in this case is Ni(Xantphos)2, which is generated in situ and not recoverable. 15 Another heterogeneous Ni catalyst is based on triazole linked organic polymer (Ni-TLOP), which acts as a photocatalyst in AAC under visible light induced condition. 16 The Ni-TLOP exhibits high catalytic performance in AAC, however, the catalyst preparation requires expensive chemicals, the catalyst becomes active only under visible light irradiation, and studied in a two-component AAC process.…”

Transition Metal‐Catalyzed Cycloaddition of Azides with Internal Alkynes

“…expanded the application of their strategy to other functionalized internal alkynes, including cyanoalkynes, thioalkynes and ynamides, all of which could offer desired trisubstituted triazoles ( 75 – 77 ) with exclusive regioselectivities (b–d, Scheme 36). [55] …”