Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

Abstract

Aryl diazonium salts occupy a privileged role in synthetic chemistry owing to their ready availability and versatile reactivity. While their applications in accessing diversely functionalized arene derivatives via denitrogenation‐coupling and reduction/addition reactions have been well recognized by practitioners in both academia and industry, recent renaissance in chemical transformations of retaining the key N2‐unit has emerged as a powerful technique to construct various N‐heterocycles. This review covers the history and latest advances in cyclization and cycloaddition reactions using aryl diazonium salts as N2‐annulation synthons. The scope, applications, and opportunities in exploring new chemical space by this sustainable strategy are summarized and discussed.

Silver‐Catalyzed [3+2] Cycloaddition Approach to Coumarin‐Decorated Tetrazoles

“…Aryldiazonium salts have captured significantly increasing attention as effective cycloaddition dipolarophiles for the construction of versatile N ‐heterocycles [9,10] . In particular, our group has disclosed a series of silver‐catalyzed [3 + 2] cycloaddition transformations between aryldiazonium salts and electron‐withdrawing group‐substituted diazo reagents since 2015 [11–13] .…”

“…Aryldiazonium salts have captured significantly increasing attention as effective cycloaddition dipolarophiles for the construction of versatile N-heterocycles. [9,10] In particular, our group has disclosed a series of silver-catalyzed [3 + 2] cycloaddition transformations between aryldiazonium salts and electron-withdrawing group-substituted diazo reagents since 2015. [11][12][13] Inspired by these precedents, we commenced the current work by employing 4-(diazomethyl)-7-acetoxy-2H-chromen-2-one 1 a and phenyldiazonium tetrafluoroborate 2 a as the model substrates (Table 1).…”

One-Pot Difunctionalization of Aryldiazonium Salts for Synthesis of para-Azophenols

“…Aryldiazonium salts by the nucleophilic addition-type reaction have also been extensively used for inserting the azo group into the target molecules ( Figure 1A ) ( Liu F et al, 2017 ; Liu Z et al, 2017 ; Abrams et al, 2018 ; Liu et al, 2018 ). Recently, cyclization by retaining the privileged N 2 fragment has been a thriving pattern in heterocyclic chemistry ( Figure 1B ) ( Mo et al, 2013 ; Zhang et al, 2020 ). Apart from the familiar aryl or/and aryl azo precursors described above, the aryl-based difunctionalization pattern of aryldiazonium salts has seriously remained in the shadow of underdevelopment.…”

Efficient reduction of nitro compounds and domino preparation of 1-substituted-1H-1,2,3,4-tetrazoles by Pd(ii)-polysalophen coated magnetite NPs as a robust versatile nanocomposite

“…1,[11][12][13] Tetrazoles have prominent biological activities in pharmaceuticals and medicine, such as antifungal, antibacterial, anti-inammatory, antihypertensive, antibiotic, anti-HIV, and anticonvulsant agents. [14][15][16] Tetrazole rings can be found in Sartans as a large group of commercial pharmaceutical compounds. 10,17 Moreover, different applications have been known for tetrazole derivatives in agriculture, photography, and various other industries.…”