Synthesis of Spirooxindoles from N-Arylamide Derivatives via Oxidative C(sp²)–C(sp³) Bond Formation Mediated by PhI(OMe)₂ Generated in Situ

Abstract

A class of novel spirooxindole compounds (2) were readily synthesized, in a metal-free environment, from N-arylamide derivatives (1) via intramolecular oxidative cyclization. Direct oxidative C­(sp2)–C­(sp3) bond formation was realized with the least-studied PhI­(OMe)2 as an oxidant, formed in situ from the reaction between PhIO and MeOH.

One‐Pot Synthesis of Primary and Secondary Aliphatic Amines via Mild and Selective sp3 C−H Imination

“…This class of hypervalent iodine reagents remains relatively understudied, offering an opportunity for new oxidative functionalization methodology. Although iodane 1 has been known for nearly forty years, [30] only one prior report describes its use as an oxidant in organic synthesis [31] . By contrast, iodane 5 was not reported prior to this and our work provides the first synthesis of 5 and the first crystal structures of both 1 and 5 .…”

IBX-Mediated Organic Transformations in Heterocyclic Chemistry-A Decade Update

“…Iodosyl benzene (PhIO) iodobenzene dichloride (PhICl 2 ), iodobenzene diacetate (PhI(OAc) 2 ), iodine trifluoroacetate [(PhI(OCOCF 3 )] 2 , Koser’s reagent-hydroxy (tosyloxy) iodobenzene (PhI(OTS)OH) (HTIB), Dess–Martin periodinane (DMP), and 2-iodoxybenzoic acid (IBX) are the widely used hypervalent iodine reagents for organic transformations ( Dong et al, 2014 ; Sun and Shi, 2014 ; Charpentier et al, 2015 ; Li et al, 2016 ; Yoshimura and Zhdankin, 2016 ; Hyatt et al, 2019 ), due to the mild reaction conditions and transition metal-free nature and operational simplicity. These are popularly employed for C–H functionalization ( Kandimalla et al, 2019 ), bifunctionalization of olefins and cyclopropane ( Banik et al, 2017 ; Muñiz et al, 2017 ), and oxidative cyclizations ( Chi et al, 2014 ; Xing et al, 2019 ; Zhen et al, 2019 ). Several articles appeared in recent literature highlighting the significance of these reagents in modern organic synthesis and in particular catalytic strategies.…”

Intramolecular Dehydrogenative Coupling Approach to 2‐Oxindoles Using Fe(OAc)2/NaI/Na2S2O8

“…[ 18,35 ] In general, besides electrochemical activation of C–H bonds, [ 20,21 ] this procedure was promoted by oxidants, such as Cu 2+ , [ 18,19,22–25,28 ] di‐ tert ‐butyl peroxide (DTBP), [ 26 ] DDQ, [ 27 ] I 2 , [ 29,33,34 ] and high‐valence iodine. [ 30–32 ] Among them, I 2 was an efficient oxidant which can promote the reaction at low temperature. [ 33 ] However, the high price of I 2 which is consumed in stoichiometric amounts hindered its application in industry.…”