Over the past few decades, hypervalent iodine chemistry has witnessed remarkable progress [
1-
15], which was partially sustained by the emergence and application of novel hypervalent iodine reagents [
16-
25]. Among the vast category of these reagents, heterocyclic iodine(Ⅲ) compounds [
26-
30], compared to their noncyclic analogues, have demonstrated the merit of higher thermal stability and unique reactivities. Accordingly, a great deal of efforts have been devoted to investigating various heterocyclic iodine(Ⅲ) reagents bearing versatile ligands including azido [
31-
35], cyano [
36-
40], trifluoromethyl [
41-
48] and triflate groups [
49-
52]. The most famous and best-investigated heterocyclic iodanes are benziodoxoles, which have achieved significant advances in their preparation, structure determination, and synthetic applications [
53-
68]. In contrast, benziodazoles, an analogous heterocyclic iodane reagent of benziodoxoles, have received relatively less attention [
69-
74]. To the best of our knowledge, there was a limited number of benziodazole reagents that have been reported till now (
Fig. 1a), and only three known transformation patterns mediated by these existing benziodazole reagents
1a-
h have been established (
Fig. 1b). In the majority of these transformations, benziodazoles were employed as ligand- or atom-transfer reagents for various functionalization reactions including azidation [
75-
78], trifluoromethylthiolation [
79,
80], aroylation [
81], fluorination [
82], and alkynylation [
83] as shown in
Fig. 1b, type 1. As an illustration, Zhang's group reported the design and synthesis of hypervalent fluoroiodane(Ⅲ) reagent
1e, which was capable of performing the intramolecular ring expansion/fluorination of unactivated cyclopropanes to afford a diverse array of 4-fully substituted fluoropiperidines [
82]. In addition, benziodazoles can also enable the oxidative coupling reactions as solely an oxidant, without incorporating any structural moieties into products (
Fig. 1b, type 2). For instance, Wang and coworkers developed a rhenium-catalyzed dehydrogenative olefination of C(sp
3)−H bonds mediated by alanine-derived hypervalent iodine(Ⅲ) reagents
1g, which is crucial for oxidizing Re(n) catalyst species from low oxidation states to high ones [
84]. Furthermore, benziodazoles may display high electrophilic reactivity and more than one structural moieties can be introduced into the corresponding product (
Fig. 1b, type 3). For example, Waser's group demonstrated that both components (alkyne ligand and benziodazole skeleton) of ethynylbenziodazolones (EBZs)
1h can be found in imidate products, which was produced from the oxyalkynylation of diazo compounds mediated by EBZs
1h [
85].