Copper(I)–Phosphinite Complexes in Click Cycloadditions: Three‐Component Reactions and Preparation of 5‐Iodotriazoles

Abstract

The remarkable activity displayed by copper(I)–phosphinite complexes of general formula [CuBr(L)] in two challenging cycloadditions is reported: a) the one‐pot azidonation/cycloaddition of boronic acids, NaN3, and terminal alkynes; b) the cycloaddition of azides and iodoalkynes. These air‐stable catalysts led to very good results in both cases and the expected triazoles could be isolated in pure form under ‘Click‐suitable’ conditions.

1-Iodobuta-1,3-diynes in Copper-Catalyzed Azide–Alkyne Cycloaddition: A One-Step Route to 4-Ethynyl-5-iodo-1,2,3-triazoles

“…Catalysts Cu­(PPh 3 ) 3 I and CuCl­(IPr), chloro­[1,3-bis­(2,6-diisopropylphenyl)­imidazol-2-ylidene]­copper­(I), were synthesized by known procedures without any modification. Benzyl azide ( 8a ), 1-(azidomethyl)-4-methoxybenzene ( 8b ), 5-(azidomethyl)-1,2,3-trimethoxybenzene ( 8c ), ethyl 2-azidoacetate ( 8d ), 1-(azidomethyl)-4-nitrobenzene ( 8f ), 6-azidohexan-1-ol ( 8g ), 1-azido-4-methoxybenzene ( 8h ), 1-azidohexane ( 8i ), 2,7-dimethylocta-3,5-diyne-2,7-diol ( 1 ), buta-1,3-diyn-1-ylbenzenes ( 4d, 5d ), tri­methyl­( p -tolylbuta-1,3-diyn-1-yl)­silane ( 6a ), ((4-meth­oxy­phenyl)­buta-1,3-diyn-1-yl)­tri­methyl­silane ( 6b ), 6-(trimethylsilyl)­hexa-3,5-diyn-1-ol ( 6c ), trimethyl­(penthyl)­silane ( 6d ), and methoxymethyltrimethylsilane ( 6e ) were synthesized using previously reported procedures.…”

“…Since the discovery, CuAAC has been also expanded for the regioselective synthesis of 5-iodo­(bromo)-1,4-disubstituted 1,2,3-triazoles starting from iodo­(bromo)­alkynes − (Scheme A) and 1-substituted 4-ethynyl-1,2,3-triazoles from either terminal diacetylenes − or trialkylsilylbuta-1,3-diynes with a one-pot desylilation − (Scheme D).…”

Bentonite ‐ Clay ‐ Supported Cuprous Iodide Nanoparticles (BENT‐ CuI NPs): A New Heterogeneous Catalyst in Diversity ‐ Oriented Synthesis of 1, 2, 3‐ Triazoles in Aqueous Medium

“…A focused literature survey as regards the choice of arylboronic acids in the synthesis of triazoles revealed that, only a limited number of protocols have earlier been reported . It is worthy to note that, using any of these protocols the synthesis of triazoles has been a two step process.…”

Regioselective Synthesis of Halotriazoles and their Utility in Metal Catalyzed Coupling Reactions

“…It was suggested that the phosphinite ligand has better tolerance in terms of functional group and steric hindrance. [ 34 ]…”