[CuBr(PPh₃)₃] for Azide−Alkyne Cycloaddition Reactions under Strict Click Conditions

Abstract

A careful methodological study revealed a true Click catalytic system based on commercially available [CuBr(PPh(3))(3)]. This system is active at room temperature, with 0.5 mol % [Cu] (or less), in the absence of any additive, and it does not require any purification step to isolate pure triazoles.

Synthesis and NMR Analysis of 1,4‐Disubstituted 1,2,3‐Triazoles Tethered to Pyridine, Pyrimidine, and Pyrazine Rings

“…The selection of this copper(I) source was based on its reportedly good performance as well as its stability towards the oxygen in air. [25] In contrast to the reactions with many other commonly used copper(I) and copper(II) compounds, the CuAAC reaction with CuBr(PPh 3 ) 3 can be conveniently conducted in an FULL PAPER open vessel, with no need for exclusion of oxygen, and without the use of sacrificial reducing reagents. Thus, by using CuBr(PPh 3 ) 3 with just 0.3-0.4 mol-% loading, the ligation of 2-picolyl azide (1C) with phenylacetylenes 2(f-j,l-n) was complete within 15 min, and the products [i.e., 5C(f-j,l-n)] were isolated in 73-88 % yield after crystallization from the appropriate solvent, as indicated in the Exp.…”

“…Tetrazolo[1,5-a]pyridine (1A), [13] tetrazolo[1,5-a]pyrimidine (1B), [21] 2-picolyl azide (1C), [23] 1-(pyridin-2-yl)prop-2-ynyl acetate (2cЈ), [27] and CuBr(PPh 3 ) 3 [25] were prepared by known procedures. 2-(Azidomethyl)pyrazine (1D) was prepared from 2-methylpyrazine according to the literature report.…”

Highly Active Dinuclear Copper Catalysts for Homogeneous Azide–Alkyne Cycloadditions

“…[46] Sulphur-based ligands are rarely used for CuAAC catalysis. However, the copper(I) [63] In this study, Díez-González also attempted the in situ preparation of the organoazide from the corresponding organic bromide and sodium azide. Albeit the organoazide was formed smoothly in DMSO or acetone, the cycloaddition reaction with phenylacetylene did not take place.…”

Copper Catalyst Activation Driven by Photoinduced Electron Transfer: A Prototype Photolatent Click Catalyst

“…[4a] CuPPh 3 CN, [21] or CuOAc [22] in solvents that provided the best activity for these catalysts in our hands: D 2 O for CuSO 4 and CuPPh 3 CN, and CD 3 OD for CuOAc (24 h reaction profiles are given in the Figure S3 of the Supporting Information).…”