Copper-catalyzed [3 + 2] cycloaddition of (phenylethynyl)di-p-tolylstibane with organic azides

Abstract

SummaryTrisubstituted 5-stibano-1H-1,2,3-triazoles were synthesized in moderate to excellent yields by the Cu-catalyzed [3 + 2] cycloaddition of a ethynylstibane with organic azides in the presence of CuBr (5 mol %) under aerobic conditions. The reaction of 5-stibanotriazole with HCl, I2, and NOBF4 afforded 1-benzyl-4-phenyltriazole, 1-benzyl-5-iodo-4-phenyltriazole, and a pentavalent organoantimony compound, respectively.

Synthesis of Fully Functionalized 5‐Selanyl‐1,2,3‐triazoles: Copper‐Catalysed Three‐Component Reaction of Ethynylstibanes, Organic Azides, and Diaryl Diselenides

“…However, the reaction with aryl azides such as 4‐methylphenyl and 4‐cyanophenyl azides gave complex mixtures. We have recently reported that 5‐stibanotriazoles could not be obtained by the Cu‐catalysed [3+2] cycloaddition of (phenylethynyl)di‐ p ‐tolylstibane with aryl‐azides . Even in the three‐component reaction, there might be a problem with the cyclization step.…”

“…Based on the above control experiments, a possible mechanism for this three‐component reaction is shown in Scheme . The reaction involves the formation of 5‐stibanotriazole 7 from ethynylstibane 1 and azide 2 in the presence of a Cu catalyst ,. [17b] Also, diaryl diselenide 3 reacts with bimetallic complex [(phen) 2 CuI 2 ] A to generate Cu III intermediate B .…”

“…To the best of our knowledge, the synthesis of fully functionalized 5‐selanyl‐1,2,3‐triazoles through Cu‐catalysed C(aryl)–Se bond formation based on a selenium‐induced reaction involving the exchange of typical elements has not been reported. Recently, we found that ethynylstibanes undergo a Cu‐catalysed azide–alkyne cycloaddition reaction with organic azides to give fully substituted 5‐organostibano‐1,2,3‐triazoles bearing antimony; these compounds could be used as versatile building blocks in chemical synthesis . As a follow up to our studies, we present in this paper the synthesis of fully functionalized 5‐selanyl‐1,2,3‐triazoles under aerobic conditions by the Cu‐catalysed three‐component reaction of ethynylstibanes, organic azides, and diaryl diselenides.…”

An Overview of 4‐ and 5‐Halo‐1,2,3‐triazoles from Cycloaddition Reactions

“…Yasuike's group reported the Cu‐catalyzed [3+2] cycloaddition of phenyl ethynylstibane with organic azides in the presence of CuBr (5 mol%) under aerobic conditions leading to trisubstituted 5‐stibano 1,2,3‐triazoles 61 . The treatment of I 2 with the 5‐stibanotriazole reacted smoothly to afford the 1‐benzyl‐5‐iodo‐4‐phenyl‐triazole 62 with a moderate yield [59] . In addition, the same group performed the formation of the 5‐iodo‐triazole by antimony (Sb) – lithium (Li) exchange reaction.…”

Transition Metal‐Catalyzed Cycloaddition of Azides with Internal Alkynes

“…Yasuike et al. investigated the performance of 1‐stibanolalkynes 21 in CuA I AC (Scheme 10b) [23] . In the presence of copper(I) bromide, 5‐stibano triazoles 22 could be prepared in up to 91% yield.…”