Diaryliodonium Salts in Transition‐Metal‐Catalyzed Chelation‐Induced C(sp²/sp³)−H Arylations

Abstract

Transition-metal-catalyzed Cross-coupling via directing group assisted CÀ H bond activation has become an expedient tool in current synthesis to achieve diverse molecular complexity. In this context, chelation-assisted arylations of C(sp 2 /sp 3)À H bonds have been extensively investigated as aryl/biaryl derivatives are an important contributor in the area of the industry, farming, medicinal and material science. The diaryliodonium salt has been broadly utilized in C(sp 2 /sp 3)À H bond arylation where the reaction proceeds via oxidative addition of aryliodonium salt to chelation induced metallacycle. The proximal/remote C(sp 2 / sp 3)À H bonds in coordination with transition metals are arylated by a range of directing groups in good to excellent yields. In this mini-review, we have outlined the up to date developments on transition-metal-catalyzed chelation assisted C(sp 2 /sp 3)À H bond arylation utilizing diaryliodonium salts as the coupling partner.

Tandem cyclization/arylation of diaryliodoniums via in situ constructed benzoxazole as a directing group for atom-economical transformation

“…Linear diaryliodoniums have become increasingly popular as effective arylating reagents in the past few years due to their availability, high reactivity, and compatibility with diverse metal catalysts. 1 Consequently, these useful hypervalent iodoniums find extensive applications in organic synthesis, materials science, pharmaceuticals, and chemical biology by forming carbon–carbon or carbon–heteroatom bonds (Scheme 1a). 2 However, compared with the significant advances in diaryliodoniums as traditional single-arylation reagents, methods for harnessing both aryl groups of them are less exploited, and only a few examples have been reported.…”

Updates on hypervalent-iodine reagents: metal-free functionalisation of alkenes, alkynes and heterocycles

“…In recent years, the strategy has been widely explored in numerous reactions such as bond construction, functionalisation, and cyclisation. 77 Recently, the Wang group developed an approach for the conversion of 4-acyl and carbamoyl dihydropyridines (DHPs) (41) into ynones (42) and ynamides with HVI reagents. The reaction occurs by the homolysis of acyl-DHP under electron activation, followed by the reaction of the resulting acyl radical with HVI(III) reagents to form the target ynones or ynamides.…”

“…[27][28][29][30][31][32][33][34][35][36][37] The chemistry of specific classes of HVI compounds has been summarised from time to time in various specialised reviews and accounts. [38][39][40][41][42][43][44][45] Thus, the present article will not be inclusive but will emphasise only the key aspects and most relevant components for this review. This article aims to give a brief synopsis of the HVI chemistry, focusing mainly on the metalfree syntheses that have taken place in the past couple of years.…”

Non-Palladium-Catalyzed Oxidative Coupling Reactions Using Hypervalent Iodine Reagents

“…The first hypervalent iodine reagent, namely, (dichloroiodo)benzene 1 was prepared by Willgerodt (1886). After this, several iodine (III) compounds such as (difluoroiodo)benzene 2, phenyliodine (III) diacetate 3 (PIDA), phenyliodine (III) bis(trifluoroacetate) 4 (PIFA), phenyliodine (III) dipivaloate 5 (PIDP), [hydroxy (tosyloxy)iodo]-benzene HTIB 6 (Koser′s reagent), iodosylbenzene 7 (PhIO), 2-iodosobenzoic acid 8 (IBA), benziodoxol (on)e reagents 9-14, and diaryliodonium salts 15-17 were identified as powerful and effective oxidants and atom transfer reagents in different organic transformations (Tohma and Kita, 2004;Joshi and De, 2021). In addition to this, cyclic iodine(V) reagents, namely, Dess-Martin periodinane (DMP) 18 and 2-iodoxybenzoic acid (IBX) 19 are strong oxidizing agents (Uyanik and Ishihara, 2009).…”