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

Abstract

Hypervalent iodine (HVI) chemistry is a rapidly growing subdomain of contemporary organic chemistry because of its enormous synthetic applications. The high nucleofugality of the phenyliodonio group (I+Ph) and their radical...

Recent Progress in Cyclic Aryliodonium Chemistry: Syntheses and Applications

“…82−87 The research focused on benziodoxol(on)es as functional-group transfer reagents has been reviewed by Togni, 15 Nachtsheim, 24 and more recently by Patel and co-workers. 88 Therefore, this type of cyclic aryliodonium will not be discussed in further detail here. Furthermore, this review aims to inspire chemical researchers to take the benefits of utilizing hypervalent iodines as environmentally reagents to accomplish the construction of more complicated compounds and to realize more diverse reaction transformations.…”

“…Moreover, the very recent development of cyclic aryliodoniums as organocatalysts, for example, halogen-bonding donors, is also included. In the past several decades, benziodoxol­(on)­es as shown in Scheme B, another unique type of cyclic aryliodoniums have been investigated extensively as functional-group transfer reagents for alkynylation, − azidation, , and trifluoromethylation (Togni’s reagents). − The research focused on benziodoxol­(on)­es as functional-group transfer reagents has been reviewed by Togni, Nachtsheim, and more recently by Patel and co-workers . Therefore, this type of cyclic aryliodonium will not be discussed in further detail here.…”

Organocatalytic synthesis of β-enaminyl radicals as single-electron donors for phenyliodine(iii) dicarboxylates: direct one-pot alkylation–aminoxidation of styrenes

“…Most recently, hypervalent iodine( iii ) reagents, such as phenyliodine( iii ) diacetate [PhI(OAc) 2 , 1a ], have been extensively used in alkylation reactions due to their environmentally benign character and easy availability. 5–8 While these reagents have been used in many alkylation reactions via polar mechanisms, many recent reports have investigated the radical alkylation reactions of these reagents. Indeed, radical decarboxylative alkylation reactions using phenyliodine( iii ) dicarboxylates ( 1 ) as alkyl radical precursors have attracted attention from chemists because of their versatility and high selectivity.…”

Hypervalent iodine(iii)-mediated oxidative dearomatization of 2H-indazoles towards indazolyl indazolones

“…On the other hand, organoiodine( iii ) compounds have witnessed significant iconic advances due to their high stability, strong electrophilicity, commercial availability, environmentally friendly nature and low toxicity. 8 Among the trivalent iodine reagents, PIFA and PIDA have been effectively implemented for the activation of aromatic rings through a single-electron-transfer (SET) oxidation process, displaying reactivity similar to metal-based oxidants like Fe( iii ), Ru( iv ), V( v ), etc. 9…”